diff --git a/src/lib/3d/Keyboard.svelte b/src/lib/3d/Keyboard.svelte
index c54e832d..5eeedeed 100644
--- a/src/lib/3d/Keyboard.svelte
+++ b/src/lib/3d/Keyboard.svelte
@@ -4,7 +4,7 @@
   import KeyboardMaterial from './KeyboardMaterial.svelte'
   import KeyboardPartGeo from './KeyboardPartGeo.svelte'
   import KeyboardKeycapGeo from './KeyboardKeycapGeo.svelte'
-  import type { CuttleKey, Geometry } from '$lib/worker/config'
+  import type { CuttleKey, Geometry, KeyboardSide } from '$lib/worker/config'
   import * as flags from '$lib/flags'
   import { keyBrightness, type KeyStatus } from './keyboardKey'
   import { hasKeyGeometry, keyUrl } from '$lib/loaders/keycaps'
@@ -23,7 +23,7 @@
   import { T } from '@threlte/core'
   import { variantURL, PART_INFO } from '$lib/geometry/socketsParts'
   import { DefaultMap } from '$lib/worker/util'
-  import { MeshStandardMaterial, Quaternion, Vector3, type Vector3Tuple, type Vector4Tuple } from 'three'
+  import { Quaternion, Vector3, type Vector3Tuple, type Vector4Tuple } from 'three'
 
   export let geometry: Geometry | null
   export let transparency: number = 100
@@ -31,7 +31,7 @@
   export let translation: number = 0
   export let flip = true
   export let reachability: boolean[] | undefined = undefined
-  export let side: 'left' | 'right' | 'unibody'
+  export let side: KeyboardSide
   export let keyColor: [any, number] | undefined = undefined
   export let trackballColor: any | undefined = undefined
   export let switchColor: [any, number] | undefined = undefined
diff --git a/src/lib/3d/KeyboardKey.svelte b/src/lib/3d/KeyboardKey.svelte
index 625a32bf..79367c92 100644
--- a/src/lib/3d/KeyboardKey.svelte
+++ b/src/lib/3d/KeyboardKey.svelte
@@ -5,7 +5,7 @@
   import type { interactivity } from '@threlte/extras'
 
   export let index: number | null
-  export let side: 'left' | 'right' | 'unibody' = 'right'
+  export let side: 'left' | 'right' | 'unibody' | 'center' = 'right'
 
   type InteractivityContext = ReturnType<typeof interactivity>
   const context: InteractivityContext = getContext('interactivity')
diff --git a/src/lib/3d/KeyboardModel.svelte b/src/lib/3d/KeyboardModel.svelte
index fdb2ce98..9744ad83 100644
--- a/src/lib/3d/KeyboardModel.svelte
+++ b/src/lib/3d/KeyboardModel.svelte
@@ -1,6 +1,6 @@
 <script lang="ts">
   import { view, noBase, noWall } from '$lib/store'
-  import type { Geometry } from '$lib/worker/config'
+  import type { Geometry, KeyboardSide } from '$lib/worker/config'
   import GroupMatrix from './GroupMatrix.svelte'
   import Microcontroller from './Microcontroller.svelte'
   import KMesh from '$lib/3d/KeyboardMeshBetter.svelte'
@@ -10,7 +10,7 @@
   export let keebGeometry: Geometry | undefined = undefined
   export let meshes: KeyboardMeshes
   export let transparency: number = 100
-  export let side: 'left' | 'right' | 'unibody'
+  export let side: KeyboardSide
 
   export let noWeb = false
 
diff --git a/src/lib/store.ts b/src/lib/store.ts
index cd53d6b7..d7ac5f2a 100644
--- a/src/lib/store.ts
+++ b/src/lib/store.ts
@@ -20,7 +20,7 @@ export const openSelect = writable<symbol | null>(null)
 
 export const hoveredKey = writable<number | null>(null)
 export const clickedKey = writable<number | null>(null)
-export const clickedSide = writable<'left' | 'right' | 'unibody' | null>(null)
+export const clickedSide = writable<'left' | 'right' | 'unibody' | 'center' | null>(null)
 export const lastKeycap = writable<number>(0)
 
 // --- Alerts -----------------------------------------------------------------
diff --git a/src/lib/worker/api.ts b/src/lib/worker/api.ts
index 33ce4d94..a2d22b1b 100644
--- a/src/lib/worker/api.ts
+++ b/src/lib/worker/api.ts
@@ -14,7 +14,7 @@ import type { BufferAttribute, BufferGeometry, Mesh } from 'three'
 import { getUser } from '../../routes/beta/lib/login'
 import { ITriangle } from '../loaders/simplekeys'
 import { type ConfError, type ConfErrors, isPro, keycapIntersections, partIntersections, socketIntersections } from './check'
-import { type Cuttleform, type CuttleKey, type Geometry, newGeometry } from './config'
+import { type Cuttleform, type CuttleKey, type Geometry, type KeyboardSide, newGeometry } from './config'
 import { boardHolder, cutWithConnector, keyHoles, makePlate, makePlateMesh, makerScrewInserts, makeWalls, type ScrewInsertTypes, webSolid } from './model'
 import { Assembly } from './modeling/assembly'
 import { blobSTL, combine, type ShapeMesh } from './modeling/index'
@@ -306,7 +306,7 @@ async function getModel(conf: Cuttleform, name: string, stitchWalls: boolean, fl
   }
 }
 
-export async function getSTL(conf: Cuttleform, name: string, side: 'left' | 'right' | 'unibody' | 'test', stitchWalls: boolean) {
+export async function getSTL(conf: Cuttleform, name: string, side: KeyboardSide | 'test', stitchWalls: boolean) {
   const flip = side == 'left'
   let model = await getModel(conf, name, stitchWalls, flip)
   if (name == 'wristrest' && side == 'unibody' && conf.wristRestRight && model) {
@@ -385,7 +385,7 @@ function meshWithVolumeAndSupport(solid: Solid, minZ: number) {
 //   return props.Mass()
 // }
 
-export async function intersections(conf: Cuttleform, side: 'left' | 'right' | 'unibody'): Promise<ConfErrors> {
+export async function intersections(conf: Cuttleform, side: KeyboardSide): Promise<ConfErrors> {
   const intersections: ConfErrors = []
   try {
     const geometry = newGeometry(conf)
diff --git a/src/lib/worker/check.ts b/src/lib/worker/check.ts
index 2f745d33..30f111f6 100644
--- a/src/lib/worker/check.ts
+++ b/src/lib/worker/check.ts
@@ -7,7 +7,7 @@ import type { Triangle } from 'three'
 import { Octree } from 'three/examples/jsm/math/Octree.js'
 import { Vector2 } from 'three/src/math/Vector2.js'
 import { calcTravel, ITriangle, simpleKey, simpleKeyPosition } from '../loaders/simplekeys'
-import type { Cuttleform, CuttleKey, Geometry } from './config'
+import type { Cuttleform, CuttleKey, Geometry, KeyboardSide } from './config'
 import { type CriticalPoints, keyHolesTrsfs2D } from './geometry'
 import { intersectPolyPoly } from './geometry.intersections'
 import Trsf, { Vector } from './modeling/transformation'
@@ -78,9 +78,7 @@ const PROPERTIES = ['aspect', 'type', 'position']
 
 export type ConfError =
   & (IntersectionError | MissingError | WrongError | OobError | InvalidError | ExceptionError | NanError | NoKeysError | WallBoundsError | WrongFormatError | SamePositionError | NotEnoughPinsError)
-  & {
-    side: 'left' | 'right' | 'unibody'
-  }
+  & { side: KeyboardSide }
 export type ConfErrors = ConfError[]
 
 export function isRenderableError(e: ConfError | undefined) {
@@ -98,7 +96,7 @@ export function salientError(e: ConfErrors): ConfError {
   return e[0]
 }
 
-export function checkConfig(conf: Cuttleform, geometry: Geometry | undefined, check3d = true, side: 'left' | 'right' | 'unibody'): ConfErrors {
+export function checkConfig(conf: Cuttleform, geometry: Geometry | undefined, check3d = true, side: KeyboardSide): ConfErrors {
   if (!conf.keys) return [{ type: 'wrongformat', side }]
   if (!conf.keys.length) return [{ type: 'nokeys', side }]
 
@@ -270,7 +268,7 @@ function prismTriangles(facePoints: Trsf[], center: Trsf, depth: number, index:
   })
 }
 
-export function* keycapIntersections(conf: Cuttleform, trsfs: Trsf[], web: ITriangle[], side: 'left' | 'right' | 'unibody') {
+export function* keycapIntersections(conf: Cuttleform, trsfs: Trsf[], web: ITriangle[], side: KeyboardSide) {
   const tree = new Octree()
   for (const tri of web) {
     tree.addTriangle(tri)
@@ -288,7 +286,7 @@ export function* keycapIntersections(conf: Cuttleform, trsfs: Trsf[], web: ITria
   yield* treeIntersections(conf, tree, 'keycap', side)
 }
 
-export function* partIntersections(conf: Cuttleform, trsfs: Trsf[], side: 'left' | 'right' | 'unibody') {
+export function* partIntersections(conf: Cuttleform, trsfs: Trsf[], side: KeyboardSide) {
   const tree = new Octree()
   for (let i = 0; i < trsfs.length; i++) {
     const key = conf.keys[i]
@@ -302,7 +300,7 @@ export function* partIntersections(conf: Cuttleform, trsfs: Trsf[], side: 'left'
   yield* treeIntersections(conf, tree, 'part', side)
 }
 
-export function* unsortedSocketIntersections(conf: Cuttleform, trsfs: Trsf[], critPts: CriticalPoints[], web: ITriangle[], side: 'left' | 'right' | 'unibody') {
+export function* unsortedSocketIntersections(conf: Cuttleform, trsfs: Trsf[], critPts: CriticalPoints[], web: ITriangle[], side: KeyboardSide) {
   const tree = new Octree()
   for (const tri of web) {
     tree.addTriangle(tri)
@@ -324,7 +322,7 @@ export function* unsortedSocketIntersections(conf: Cuttleform, trsfs: Trsf[], cr
  * Every socket-socket intersection will generate a socket->wall intersection as well,
  * but the socket-socket intersections are easier to debug so they should get priority.
  */
-export function* socketIntersections(conf: Cuttleform, trsfs: Trsf[], critPts: CriticalPoints[], web: ITriangle[], side: 'left' | 'right' | 'unibody') {
+export function* socketIntersections(conf: Cuttleform, trsfs: Trsf[], critPts: CriticalPoints[], web: ITriangle[], side: KeyboardSide) {
   const socketSocketIntersections: ConfError[] = []
   const socketWallIntersections: ConfError[] = []
   for (const intersection of unsortedSocketIntersections(conf, trsfs, critPts, web, side)) {
@@ -343,7 +341,7 @@ function* treeIntersections(
   conf: Cuttleform,
   tree: Octree,
   what: 'keycap' | 'socket' | 'part',
-  side: 'left' | 'right' | 'unibody',
+  side: KeyboardSide,
   ignoreTouching = false,
   intersected?: DefaultMap<number, Map<number, boolean>> | undefined,
 ): Generator<ConfError> {
diff --git a/src/lib/worker/config.cosmos.ts b/src/lib/worker/config.cosmos.ts
index b0426378..0a344a00 100644
--- a/src/lib/worker/config.cosmos.ts
+++ b/src/lib/worker/config.cosmos.ts
@@ -2,15 +2,16 @@ import ETrsf, { Constant, fullMirrorETrsf, type MatrixOptions, mirror } from '$l
 // import { deserialize } from 'src/routes/beta/lib/serialize'
 import { DEFAULT_LAYOUT, flippedKey } from '$lib/geometry/layouts'
 import { decodeVariant, encodeVariant, PART_INFO, socketSize } from '$lib/geometry/socketsParts'
-import type { ClusterName, ClusterSide, ClusterType, Connector, Layout, PartVariant, ScrewFlags } from '$target/cosmosStructs'
+import type { ClusterName, ClusterType, Connector, Layout, PartVariant, ScrewFlags } from '$target/cosmosStructs'
 import { decodeClusterFlags, encodeClusterFlags } from '$target/cosmosStructs'
 import type { Curvature } from '$target/proto/cosmos'
 import { Matrix4, Vector3 } from 'three'
-import { type AnyShell, curvature, type Cuttleform, type CuttleKey, decodeTuple, encodeTuple, type FullCuttleform, type Keycap, matrixToRPY, tupleToRot, tupleToXYZ } from './config'
+import { type AnyShell, curvature, type Cuttleform, type CuttleKey, decodeTuple, encodeTuple, type FullCuttleform, type KeyboardSide, type Keycap, matrixToRPY, tupleToRot, tupleToXYZ } from './config'
 import { decodePartType, encodePartType, KEYBOARD_DEFAULTS, LETTERS } from './config.serialize'
 import Trsf from './modeling/transformation'
-import { capitalize, DefaultMap, objEntries, objKeys, sum, TallyMap, trimUndefined } from './util'
+import { capitalize, DefaultMap, match, objEntries, objKeys, sum, TallyMap, trimUndefined } from './util'
 
+export type ClusterSide = 'left' | 'right' | 'center'
 export type CustomConnector = {
   preset?: undefined
   width: number
@@ -108,6 +109,7 @@ export type CosmosKeyboard =
     wristRestPosition: bigint
     connectorLeftIndex: number
     connectorRightIndex: number
+    connectorCenterIndex: number
     connectors: ConnectorMaybeCustom[]
     mirrorConnectors: boolean
     plate: Cuttleform['plate']
@@ -149,6 +151,7 @@ export function getRowColumn(t: ETrsf) {
 export function sortClusters(clusters: CosmosCluster[]) {
   const val = (c: CosmosCluster) => {
     let v = 0
+    if (c.side == 'center') v += 5
     if (c.side == 'left') v += 10
     if (c.name == 'thumbs') v += 1
     return v
@@ -156,7 +159,7 @@ export function sortClusters(clusters: CosmosCluster[]) {
   return clusters.sort((a, b) => val(a) - val(b))
 }
 
-function toCosmosClusters(keys: CuttleKey[], side: 'left' | 'right', globalProfile: Keycap['profile'], globalPartType: PartType, globalCurvature: Curvature, wrOriginInv: Trsf) {
+function toCosmosClusters(keys: CuttleKey[], side: ClusterSide, globalProfile: Keycap['profile'], globalPartType: PartType, globalCurvature: Curvature, wrOriginInv: Trsf) {
   const clusters: CosmosCluster[] = []
 
   for (const [name, trsfGrp] of collectByClusterName(keys).entries()) {
@@ -164,6 +167,8 @@ function toCosmosClusters(keys: CuttleKey[], side: 'left' | 'right', globalProfi
     const clusterProfile = dominantProfile(trsfGrp) ?? globalProfile
     const clusterPartType = decodePartType(dominantPartType(trsfGrp) ?? encodePartType(globalPartType))
     const clusterType = decodeClusterFlags(dominantClusterType(trsfGrp, side))
+    // Restore the runtime side='center' after decoding (encode wrote bit-side='right').
+    if (side === 'center') (clusterType as any).side = 'center'
     const clusterTrsf = getTransformBy(trsfGrp[0])!
     const cluster: CosmosCluster = {
       ...clusterType,
@@ -184,6 +189,7 @@ function toCosmosClusters(keys: CuttleKey[], side: 'left' | 'right', globalProfi
       const columnPartType = decodePartType(dominantPartType(colGrp) ?? encodePartType(clusterPartType))
       const columnStagger = dominantStagger(colGrp)
       const columnType = decodeClusterFlags(dominantClusterType(colGrp, side))
+      if (side === 'center') (columnType as any).side = 'center'
       let columnTrsf = new Trsf().fromMatrix(columnStagger.split(',').map(Number))
       if (columnStagger.startsWith('!')) {
         columnTrsf = new Trsf().fromMatrix(columnStagger.slice(1).split(',').map(Number))
@@ -227,6 +233,7 @@ function toCosmosClusters(keys: CuttleKey[], side: 'left' | 'right', globalProfi
           partType: {
             type: diff(colKey.type, columnPartType.type),
             aspect: diff(colKey.aspect, columnPartType.aspect),
+            variant: colKey.variant ? encodeVariant(colKey.type, colKey.variant) : undefined,
           },
           profile: {
             profile: diff(keycap?.profile, columnProfile ?? clusterProfile ?? globalProfile),
@@ -255,8 +262,10 @@ function toCosmosClusters(keys: CuttleKey[], side: 'left' | 'right', globalProfi
     position: undefined,
     rotation: undefined,
   }
-  if (!clusters.find(c => c.name == 'fingers')) clusters.push({ ...defaultCluster, name: 'fingers' })
-  if (!clusters.find(c => c.name == 'thumbs')) clusters.push({ ...defaultCluster, name: 'thumbs' })
+  if (side !== 'center') {
+    if (!clusters.find(c => c.name == 'fingers')) clusters.push({ ...defaultCluster, name: 'fingers' })
+    if (!clusters.find(c => c.name == 'thumbs')) clusters.push({ ...defaultCluster, name: 'thumbs' })
+  }
   return clusters
 }
 
@@ -284,10 +293,15 @@ export function toFullCosmosConfig(conf: FullCuttleform, flipLeft = false): Cosm
   for (const [side, config] of objEntries(conf)) {
     if (!kbd) kbd = toCosmosConfig(config!, side, false, flipLeft)
     else {
-      const c = toCosmosConfig(config!, side, false, flipLeft)
+      const c = toCosmosConfig(config!, side, false, flipLeft, {
+        globalCurvature: kbd.curvature,
+        globalPartType: kbd.partType,
+        globalProfile: kbd.profile,
+      })
       kbd.clusters.push(...c.clusters)
       if (side == 'left') kbd.connectorLeftIndex = c.connectorLeftIndex
       if (side == 'right') kbd.connectorRightIndex = c.connectorRightIndex
+      if (side == 'center') kbd.connectorCenterIndex = c.connectorCenterIndex
     }
   }
   if (!kbd) throw new Error('No configuration for keyboard')
@@ -311,10 +325,16 @@ export function toFullCosmosConfig(conf: FullCuttleform, flipLeft = false): Cosm
   return kbd
 }
 
-export function toCosmosConfig(conf: Cuttleform, side: 'left' | 'right' | 'unibody', overrideWristRest: boolean, flipLeft = false): CosmosKeyboard {
-  const globalCurvature = dominantCurvature(conf.keys)
-  const globalProfile = dominantProfile(conf.keys) ?? 'xda'
-  const globalPartType = decodePartType(dominantPartType(conf.keys) ?? encodePartType({ type: 'mx-better', aspect: 1 }))
+type ToCosmosConfigOpts = {
+  globalCurvature: CosmosKeyboard['curvature']
+  globalProfile: CosmosKeyboard['profile']
+  globalPartType: Required<PartType>
+}
+
+export function toCosmosConfig(conf: Cuttleform, side: KeyboardSide, overrideWristRest: boolean, flipLeft = false, opts?: ToCosmosConfigOpts): CosmosKeyboard {
+  const globalCurvature = opts?.globalCurvature ?? dominantCurvature(conf.keys)
+  const globalProfile = opts?.globalProfile ?? dominantProfile(conf.keys) ?? 'xda'
+  const globalPartType = opts?.globalPartType ?? decodePartType(dominantPartType(conf.keys) ?? encodePartType({ type: 'mx-better', aspect: 1 }))
   const wrOrigin = new ETrsf(conf.wristRestOrigin.history).evaluate({ flat: false }, new Trsf())
   const wrOriginInv = overrideWristRest ? wrOrigin.inverted() : new Trsf()
   const flippedWrOriginInv = overrideWristRest ? fullMirrorETrsf(conf.wristRestOrigin).evaluate({ flat: false }).invert() : new Trsf()
@@ -345,8 +365,9 @@ export function toCosmosConfig(conf: Cuttleform, side: 'left' | 'right' | 'unibo
     shell: conf.shell,
     plate: conf.plate,
     wristRestEnable: !!conf.wristRestRight,
-    connectorLeftIndex: conf.connectorIndex,
-    connectorRightIndex: conf.connectorIndex,
+    connectorLeftIndex: side === 'center' ? -1 : conf.connectorIndex,
+    connectorRightIndex: side === 'center' ? -1 : conf.connectorIndex,
+    connectorCenterIndex: side === 'center' ? conf.connectorIndex : -1,
     unibody: side == 'unibody',
     layout: DEFAULT_LAYOUT,
     wristRestProps: conf.wristRestRight
@@ -375,6 +396,7 @@ export function toCosmosConfig(conf: Cuttleform, side: 'left' | 'right' | 'unibo
       ? [
         ...toCosmosClusters(filterUnibodySide(conf.keys, 'right'), 'right', globalProfile, globalPartType, globalCurvature, wrOriginInv),
         ...toCosmosClusters(filterUnibodySide(conf.keys, 'left'), 'left', globalProfile, globalPartType, globalCurvature, flippedWrOriginInv),
+        ...toCosmosClusters(conf.keys.filter(k => k.cluster === 'center'), 'center', globalProfile, globalPartType, globalCurvature, wrOriginInv),
       ]
       : toCosmosClusters(conf.keys, side, globalProfile, globalPartType, globalCurvature, wrOriginInv),
   }
@@ -383,11 +405,12 @@ export function toCosmosConfig(conf: Cuttleform, side: 'left' | 'right' | 'unibo
   return keyboard
 }
 
-/** Estimate which side of the keyboard a key is on */
+/** Estimate which side of the keyboard a key is on. Center-cluster keys are excluded — they're handled separately. */
 function filterUnibodySide(keys: CuttleKey[], side: 'left' | 'right') {
-  const xs = keys.map(k => k.position.evaluate({ flat: false }).origin().x)
+  const sideKeys = keys.filter(k => k.cluster !== 'center')
+  const xs = sideKeys.map(k => k.position.evaluate({ flat: false }).origin().x)
   const center = sum(xs) / xs.length
-  return keys.filter((k, i) => side == 'left' ? (xs[i] < center) : (xs[i] > center))
+  return sideKeys.filter((k, i) => side == 'left' ? (xs[i] < center) : (xs[i] > center))
 }
 
 function dominantCurvature(keys: CuttleKey[]): CosmosKeyboard['curvature'] {
@@ -431,7 +454,7 @@ function dominantCurvature(keys: CuttleKey[]): CosmosKeyboard['curvature'] {
   }
 }
 
-export function sideFromCosmosConfig(c: CosmosKeyboard, side: 'left' | 'right' | 'unibody', flipLeft = true): Cuttleform | undefined {
+export function sideFromCosmosConfig(c: CosmosKeyboard, side: KeyboardSide, flipLeft = true): Cuttleform | undefined {
   const wrPos = decodeTuple(c.wristRestPosition)
   const conf: Cuttleform = {
     wallThickness: c.wallThickness,
@@ -451,12 +474,13 @@ export function sideFromCosmosConfig(c: CosmosKeyboard, side: 'left' | 'right' |
     clearScrews: c.clearScrews,
     rounded: JSON.parse(JSON.stringify(c.rounded)),
     connectors: c.connectors,
-    connectorIndex: side == 'left' ? c.connectorLeftIndex : c.connectorRightIndex,
+    connectorIndex: match(side, { left: c.connectorLeftIndex, center: c.connectorCenterIndex }, c.connectorRightIndex),
     microcontroller: c.microcontroller,
     microcontrollerAngle: c.microcontrollerAngle,
     fastenMicrocontroller: c.fastenMicrocontroller,
     flipConnectors: side == 'left' && !c.mirrorConnectors,
-    wristRestLeft: c.wristRestEnable
+    // Center piece never has a wrist rest.
+    wristRestLeft: side != 'center' && c.wristRestEnable
       ? {
         angle: c.wristRestProps.angle,
         taper: c.wristRestProps.taper,
@@ -467,7 +491,7 @@ export function sideFromCosmosConfig(c: CosmosKeyboard, side: 'left' | 'right' |
         extension: c.wristRestProps.extensionLeft,
       }
       : undefined,
-    wristRestRight: c.wristRestEnable
+    wristRestRight: side != 'center' && c.wristRestEnable
       ? {
         angle: c.wristRestProps.angle,
         taper: c.wristRestProps.taper,
@@ -483,16 +507,14 @@ export function sideFromCosmosConfig(c: CosmosKeyboard, side: 'left' | 'right' |
     plate: c.plate,
   }
   const clusters: CosmosCluster[] = c.clusters.filter(c => side == 'unibody' || c.side == side)
+  // Add mirrored fingers
   if (side == 'left' && !c.clusters.find(c => c.side == 'left' && c.name == 'fingers')) clusters.unshift(mirrorCluster(c.clusters.find(c => c.side == 'right' && c.name == 'fingers')!, c))
-  if (side == 'unibody' && !c.clusters.find(c => c.side == 'left' && c.name == 'fingers')) {
-    clusters.splice(
-      2,
-      0,
-      mirrorCluster(c.clusters.find(c => c.side == 'right' && c.name == 'fingers')!, c),
-    )
-  }
-  if (side != 'right' && !c.clusters.find(c => c.side == 'left' && c.name == 'thumbs')) clusters.push(mirrorCluster(c.clusters.find(c => c.side == 'right' && c.name == 'thumbs')!, c))
-  // console.log('CLUSTERS', clusters)
+  if (side == 'unibody' && !c.clusters.find(c => c.side == 'left' && c.name == 'fingers')) clusters.splice(2, 0, mirrorCluster(c.clusters.find(c => c.side == 'right' && c.name == 'fingers')!, c))
+  // Add mirrored thumbs
+  if ((side == 'left' || side == 'unibody') && !c.clusters.find(c => c.side == 'left' && c.name == 'thumbs')) {
+    clusters.push(mirrorCluster(c.clusters.find(c => c.side == 'right' && c.name == 'thumbs')!, c))
+  }
+
   for (const clusterA of clusters) {
     for (const clusterB of clusterA.clusters) {
       for (const key of clusterB.keys) {
@@ -532,14 +554,17 @@ export function toCuttleKey(c: CosmosKeyboard, cluster: CosmosCluster, col: Cosm
 }
 
 export function fromCosmosConfig(c: CosmosKeyboard, flipLeft = true): FullCuttleform {
-  return c.unibody
-    ? {
-      unibody: sideFromCosmosConfig(c, 'unibody', flipLeft),
-    }
-    : {
-      left: sideFromCosmosConfig(c, 'left', flipLeft),
-      right: sideFromCosmosConfig(c, 'right', flipLeft),
-    }
+  if (c.unibody) {
+    return { unibody: sideFromCosmosConfig(c, 'unibody', flipLeft) }
+  }
+  const result: FullCuttleform = {
+    left: sideFromCosmosConfig(c, 'left', flipLeft),
+    right: sideFromCosmosConfig(c, 'right', flipLeft),
+  }
+  if (c.clusters.some(cl => cl.side === 'center' && cl.clusters.length > 0)) {
+    result.center = sideFromCosmosConfig(c, 'center', flipLeft)
+  }
+  return result
 }
 
 // /** Determines how much the thumb cluster shifts when the thumb origin is moved from  */
@@ -549,7 +574,8 @@ export function fromCosmosConfig(c: CosmosKeyboard, flipLeft = true): FullCuttle
 
 /** Calculate the cluster trsf, accounting for the fact that everything rotates in flat mode by fingers key rotation */
 export function calcClusterTrsf(cluster: CosmosCluster, keeb: CosmosKeyboard) {
-  if (cluster.name == 'fingers') return rotationPositionETrsf(cluster, false)
+  // Center clusters and fingers use absolute world-space positioning.
+  if (cluster.name == 'fingers' || cluster.side == 'center') return rotationPositionETrsf(cluster, false)
 
   const fingerCluster = keeb.clusters.find(c => c.side == cluster.side && c.name == 'fingers') || mirrorCluster(keeb.clusters.find(c => c.name == 'fingers')!, keeb)
   const fingerPos = rotationPositionETrsf(fingerCluster, false) || new ETrsf()
@@ -696,7 +722,7 @@ function rotateColumnStagger(stagger: Trsf, col: number, curvature: Curvature) {
   return stagger.premultiplied(columnRotation.inverted()).multiply(columnRotation)
 }
 
-function dominantClusterType(keys: CuttleKey[], side: 'right' | 'left') {
+function dominantClusterType(keys: CuttleKey[], side: ClusterSide) {
   const clusterNames = new TallyMap<ClusterName>()
   const clusterTypes = new TallyMap<ClusterType>()
   for (const key of keys) {
@@ -704,7 +730,12 @@ function dominantClusterType(keys: CuttleKey[], side: 'right' | 'left') {
     if (key.position.history.find(h => h.name == 'placeOnMatrix')) clusterTypes.incr('matrix')
     if (key.position.history.find(h => h.name == 'placeOnSphere')) clusterTypes.incr('sphere')
   }
-  return encodeClusterFlags({ type: clusterTypes.max() ?? 'matrix', name: clusterNames.max() ?? 'fingers', side })
+  // Side 'center' is encoded via name='center' (bit-side='right'). The runtime
+  // side is restored on decode; the bitfield only cares about the encoded name.
+  const isCenter = side === 'center'
+  const name = isCenter ? 'center' : (clusterNames.max() ?? 'fingers')
+  const sideForFlags: ClusterSide = isCenter ? 'right' : side
+  return encodeClusterFlags({ type: clusterTypes.max() ?? 'matrix', name, side: sideForFlags })
 }
 
 function getTransformBy(key: CuttleKey) {
@@ -728,7 +759,7 @@ function collectByTransformBy(keys: CuttleKey[]) {
 function collectByClusterName(keys: CuttleKey[]) {
   const names = new DefaultMap<ClusterName, CuttleKey[]>(() => [])
   for (const key of keys) {
-    const cluster = key.cluster == 'thumbs' ? key.cluster : 'fingers'
+    const cluster: ClusterName = match(key.cluster, { 'thumbs': 'thumbs', 'center': 'center' }, 'fingers')
     names.get(cluster).push(key)
   }
   return names
@@ -865,13 +896,21 @@ function nKeysInCluster(cl: CosmosCluster) {
 }
 
 /** Find the index of the nth key after filtering all keys to a certain side */
-export function nthIndex(conf: CosmosKeyboard, side: 'right' | 'left' | 'unibody', cuttleInd: number) {
+export function nthIndex(conf: CosmosKeyboard, side: 'right' | 'left' | 'center' | 'unibody', cuttleInd: number) {
   if (!conf) return null
   const rightFingerCluster = conf.clusters.find(c => c.name == 'fingers' && c.side == 'right')!
   const rightThumbCluster = conf.clusters.find(c => c.name == 'thumbs' && c.side == 'right')!
+  const centerCluster = conf.clusters.find(c => c.side == 'center')
 
   const nRightKeys = nKeysInCluster(rightFingerCluster) + nKeysInCluster(rightThumbCluster)
-  const offset = side == 'right' ? 0 : nRightKeys
+  const nCenterKeys = centerCluster ? nKeysInCluster(centerCluster) : 0
+
+  // Center cluster is sorted between right and left (sortClusters places it at val=5..6).
+  if (side == 'center') {
+    return cuttleInd + nRightKeys
+  }
+
+  const offset = side == 'right' ? 0 : nRightKeys + nCenterKeys
   const fingerCluster = conf.clusters.find(c => c.name == 'fingers' && c.side == side)
   const thumbCluster = conf.clusters.find(c => c.name == 'thumbs' && c.side == side)
 
@@ -883,11 +922,18 @@ export function nthIndex(conf: CosmosKeyboard, side: 'right' | 'left' | 'unibody
     const leftThumbCluster = conf.clusters.find(c => c.name == 'thumbs' && c.side == 'left')
     const nFingerKeys = nKeysInCluster(leftFingerCluster || rightFingerCluster)
 
-    if (leftFingerCluster && leftThumbCluster) return cuttleInd
-    if (!leftFingerCluster && !leftThumbCluster) return cuttleInd - nRightKeys
-    if (!leftFingerCluster && leftThumbCluster) return cuttleInd - (cuttleInd < nRightKeys + nFingerKeys ? nRightKeys : nFingerKeys)
-    if (cuttleInd < nRightKeys + nFingerKeys) return cuttleInd
-    return cuttleInd - nFingerKeys + nKeysInCluster(rightFingerCluster) - nRightKeys
+    // Center keys sit between right and left in the global ordering.
+    if (centerCluster && cuttleInd >= nRightKeys && cuttleInd < nRightKeys + nCenterKeys) {
+      return cuttleInd
+    }
+    // Adjust cuttleInd back to the left-keys offset that the original logic expects.
+    const adjusted = cuttleInd - (centerCluster && cuttleInd >= nRightKeys ? nCenterKeys : 0)
+
+    if (leftFingerCluster && leftThumbCluster) return adjusted + (centerCluster && cuttleInd >= nRightKeys ? nCenterKeys : 0)
+    if (!leftFingerCluster && !leftThumbCluster) return adjusted - nRightKeys
+    if (!leftFingerCluster && leftThumbCluster) return adjusted - (adjusted < nRightKeys + nFingerKeys ? nRightKeys : nFingerKeys)
+    if (adjusted < nRightKeys + nFingerKeys) return adjusted
+    return adjusted - nFingerKeys + nKeysInCluster(rightFingerCluster) - nRightKeys
   }
 
   if (cuttleInd < nFingerKeys) {
@@ -916,6 +962,7 @@ function mirrorRotationTuple(t: bigint | undefined) {
 }
 
 export function mirrorCluster(clr: CosmosCluster, kbd: CosmosKeyboard | undefined, flipLetters = true): CosmosCluster {
+  if (clr.side === 'center') return clr // Center clusters don't get mirrored
   return {
     ...clr,
     curvature: { ...clr.curvature },
diff --git a/src/lib/worker/config.serialize.ts b/src/lib/worker/config.serialize.ts
index 7824c34b..d8325f8b 100644
--- a/src/lib/worker/config.serialize.ts
+++ b/src/lib/worker/config.serialize.ts
@@ -4,6 +4,7 @@
 
 import { BinaryReader, BinaryWriter } from '@protobuf-ts/runtime'
 import {
+  type ClusterFlags,
   decodeBasicShellFlags,
   decodeClusterFlags,
   decodeConnector,
@@ -125,6 +126,19 @@ function decodeConnectorsCompatible(connectors: Uint8Array, connector: number |
   return decodeConnectors(connectors)
 }
 
+// Special handling for center cluster
+function decodeClusterFlagsCorrectly(idType: number) {
+  const flags = decodeClusterFlags(idType)
+  if (flags.name === 'center') return { ...flags, side: 'center' as const }
+  return flags
+}
+function encodeClusterFlagsCorrectly(c: ReturnType<typeof decodeClusterFlagsCorrectly>) {
+  return encodeClusterFlags({
+    ...c,
+    side: c.side == 'center' ? 'right' : c.side,
+  })
+}
+
 // ----------  PROFILES ----------
 // dprint-ignore
 export const LETTERS = [
@@ -244,6 +258,7 @@ const KEYBOARD_EXTRA_DEFAULTS: KeyboardExtra = {
   wristRestRightExtension: 80,
   connectorLeftIndex: -10,
   connectorRightIndex: -10,
+  connectorCenterIndex: -10,
   screwIndices: [],
   microcontrollerAngle: 0,
   plateThickness: 30,
@@ -420,7 +435,7 @@ export function decodeCosmosCluster(clusterA: Cluster): CosmosCluster {
   let lastCluster: Cluster | null = null
 
   return {
-    ...decodeClusterFlags(clusterA.idType ?? 0),
+    ...decodeClusterFlagsCorrectly(clusterA.idType ?? 0),
     curvature: decodeCurvature(clusterA.curvature || {}),
     profile: decodeProfile(clusterA.keyProfile || 0).profile,
     partType: decodePartType(clusterA.partType || 0),
@@ -435,7 +450,7 @@ export function decodeCosmosCluster(clusterA: Cluster): CosmosCluster {
       let lastKey: Key | null = null
       let lastKeyRow = 0
       return {
-        ...decodeClusterFlags(clusterB.idType ?? clusterA.idType ?? 0),
+        ...decodeClusterFlagsCorrectly(clusterB.idType ?? clusterA.idType ?? 0),
         curvature: decodeCurvature(clusterB.curvature || {}),
         profile: decodeProfile(clusterB.keyProfile || 0).profile,
         partType: decodePartType(clusterB.partType || 0),
@@ -522,6 +537,7 @@ export function decodeConfigIdk(b64: string): CosmosKeyboard {
     wristRestPosition: keeb.wristRestPosition,
     connectorLeftIndex: keebExtra.connectorLeftIndex / 10,
     connectorRightIndex: keebExtra.connectorRightIndex / 10,
+    connectorCenterIndex: keebExtra.connectorCenterIndex / 10,
     clusters: keeb.cluster.map(decodeCosmosCluster),
     plate: hasSpecialPlate
       ? {
@@ -615,7 +631,7 @@ function decodeCurvature(c: Curvature): Curvature {
 
 export function encodeCosmosCluster(clusterA: CosmosCluster): Cluster {
   const cluster: Cluster = {
-    idType: encodeClusterFlags(clusterA),
+    idType: encodeClusterFlagsCorrectly(clusterA),
     cluster: [],
     key: [],
     partType: diff(encodePartType(clusterA.partType), 0),
@@ -629,7 +645,7 @@ export function encodeCosmosCluster(clusterA: CosmosCluster): Cluster {
   for (const clusterB of clusterA.clusters) {
     const col = clusterB.column
     const column: Cluster = {
-      idType: diff(encodeClusterFlags(clusterB), cluster.idType),
+      idType: diff(encodeClusterFlagsCorrectly(clusterB), cluster.idType),
       cluster: [],
       key: [],
       partType: diff(encodePartType(clusterB.partType), 0),
@@ -720,6 +736,7 @@ export function encodeCosmosConfig(conf: CosmosKeyboard): Keyboard {
       wristRestRightExtension: Math.round(conf.wristRestProps.extensionRight * 10),
       connectorLeftIndex: Math.round(conf.connectorLeftIndex * 10),
       connectorRightIndex: Math.round(conf.connectorRightIndex * 10),
+      connectorCenterIndex: Math.round(conf.connectorCenterIndex * 10),
       screwIndices: conf.screwIndices.some(c => c >= 0) ? conf.screwIndices.map(i => Math.round(i * 10) + 10) : [],
       roundedSideConcavity: conf.rounded.side ? Math.round(conf.rounded.side.concavity * 10) : undefined,
       roundedSideDivisor: conf.rounded.side ? Math.round(conf.rounded.side.divisor * 10) : undefined,
diff --git a/src/lib/worker/config.test.ts b/src/lib/worker/config.test.ts
index 078b7aeb..9f98797f 100644
--- a/src/lib/worker/config.test.ts
+++ b/src/lib/worker/config.test.ts
@@ -3,6 +3,7 @@ import { expect, test } from 'bun:test'
 import { Quaternion } from 'three'
 import { toCode } from '../../../src/routes/beta/lib/editor/toCode'
 import { deserialize, toCuttleformProto } from '../../../src/routes/beta/lib/serialize'
+import { setPreset } from '../../routes/beta/lib/editor/visualEditorHelpers'
 import { cuttleConf, type Cuttleform, type FullCuttleform } from './config'
 import { type ConnectorMaybeCustom, type CosmosCluster, type CosmosKey, type CosmosKeyboard, fromCosmosConfig, toCosmosConfig, toFullCosmosConfig } from './config.cosmos'
 import { decodeConfigIdk, decodeConnectors, encodeConnectors, encodeCosmosConfig, serializeCosmosConfig } from './config.serialize'
@@ -103,6 +104,34 @@ test('Ensure long letters are saved', () => {
   expect(decoded.clusters[0].clusters[0].keys[0].profile.letter).toEqual('LOOOONG')
 })
 
+test('Center cluster encoding round-trip', () => {
+  const config = cuttleConf(defaultConfig.options as any)
+  const cosmos = toCosmosConfig(config, 'right', true)
+  cosmos.wristRestPosition = 0n
+  cosmos.connectorCenterIndex = 7
+  setPreset(cosmos, 'center', 'trackball', 'center')
+
+  const encoded = serializeCosmosConfig(encodeCosmosConfig(cosmos))
+  const decoded = decodeConfigIdk(encoded)
+
+  const decodedCenter = decoded.clusters.find(c => c.side === 'center')
+  expect(decodedCenter).toBeDefined()
+  expect(decodedCenter!.name).toBe('center')
+  expect(decodedCenter!.side).toBe('center')
+  expect(decodedCenter!.clusters[0].side).toBe('center')
+  expect(decodedCenter!.clusters[0].name).toBe('center')
+  expect(decoded.connectorCenterIndex).toBe(7)
+})
+
+test('Old URL without center cluster decodes cleanly', () => {
+  // The default-config URL — does NOT contain a center cluster
+  const encoded =
+    'Cn8KDxIFEIA/ICcSABIAEgA4MQoPEgUQgEsgJxIAEgASADgdChwSBRCAVyAnEgASABIDELAvEgMQsF84CUCE8LwCChcSBRCAYyAnEgASABIDELA7EgMQsGs4CgoVEgUQgG8gJxIAEgASADgeQJCGirAHGABA6IWgrvBVSNzwoqABCpIBChcSExDAwAJAgICYAkjCmaCVkLwBUEM4CAoVEhAQQECAgCBI0JWA3ZD1A1ALUJ4CChYSEhBAQICAzAJIwpmglZC8AVCGAVA6ChQSEBBAQICA+AFI5pn8p5ALUFdQfwoVEhAQQECAgKQDSPCZzLXQMFB0UJUBGAIiCgjIARDIARgAIABAy4uEpNAxSK2R3I3BkwZyAA=='
+  const cosmos = decodeConfigIdk(encoded)
+  expect(cosmos.clusters.find(c => c.side === 'center')).toBeUndefined()
+  expect(cosmos.connectorCenterIndex).toBe(-1)
+})
+
 test('Encoding connectors', () => {
   const connectors: ConnectorMaybeCustom[] = [
     { preset: 'trrs' },
diff --git a/src/lib/worker/config.ts b/src/lib/worker/config.ts
index 6f47dd8c..482507eb 100644
--- a/src/lib/worker/config.ts
+++ b/src/lib/worker/config.ts
@@ -144,8 +144,10 @@ export type Cuttleform = SpecificCuttleform<AnyShell>
 export type FullCuttleform = {
   left?: Cuttleform
   right?: Cuttleform
+  center?: Cuttleform
   unibody?: Cuttleform
 }
+export type KeyboardSide = 'left' | 'right' | 'center' | 'unibody'
 
 export interface BasicShell {
   type: 'basic'
@@ -1518,6 +1520,7 @@ export function newFullGeometry(c: FullCuttleform): FullGeometry {
   const geo: FullGeometry = {}
   if (c.left) geo.left = newGeometry(c.left)
   if (c.right) geo.right = newGeometry(c.right)
+  if (c.center) geo.center = newGeometry(c.center)
   if (c.unibody) geo.unibody = newGeometry(c.unibody)
   return geo
 }
@@ -1526,13 +1529,17 @@ export function setBottomZ(conf: FullCuttleform) {
   if (conf.left && conf.right) {
     const botLeft = newGeometry(conf.left).bottomZ
     const botRight = newGeometry(conf.right).bottomZ
-    conf.left.bottomZ = conf.right.bottomZ = Math.min(botLeft, botRight)
+    const botCenter = conf.center ? newGeometry(conf.center).bottomZ : Infinity
+    const bot = Math.min(botLeft, botRight, botCenter)
+    conf.left.bottomZ = conf.right.bottomZ = bot
+    if (conf.center) conf.center.bottomZ = bot
   }
 }
 
 export type Center = {
   left?: Point
   right?: Point
+  center?: Point
   unibody?: Point
 }
 export type FullCenter = Full<Center>
@@ -1549,22 +1556,20 @@ export function fullEstimatedCenter(geo: FullGeometry | undefined, withWristRest
   } else {
     const leftBB = estimatedBB(geo.left, withWristRest && !!geo.left?.c.wristRestRight)
     const rightBB = estimatedBB(geo.right, withWristRest && !!geo.right?.c.wristRestRight)
-    const sepDiff = (VIEW_SEPARATION - (rightBB[0] + leftBB[0])) / 2
+    const centerBB = geo.center ? estimatedBB(geo.center) : null
+    let sepDiff = (VIEW_SEPARATION - (rightBB[0] + leftBB[0])) / 2
+    if (centerBB) sepDiff += VIEW_SEPARATION / 2 + (centerBB[1] - centerBB[0]) / 2
+
+    const centerY = (Math.min(leftBB[2], rightBB[2]) + Math.max(leftBB[3], rightBB[3])) / 2
+    const centerZ = (Math.min(leftBB[4], rightBB[4]) + Math.max(leftBB[5], rightBB[5])) / 2
     return {
       left: {
         left: [-(leftBB[0] + leftBB[1]) / 2, (leftBB[2] + leftBB[3]) / 2, (leftBB[4] + leftBB[5]) / 2],
       },
       both: {
-        left: [
-          (rightBB[1] - leftBB[1]) / 2 + sepDiff,
-          (Math.min(leftBB[2], rightBB[2]) + Math.max(leftBB[3], rightBB[3])) / 2,
-          (Math.min(leftBB[4], rightBB[4]) + Math.max(leftBB[5], rightBB[5])) / 2,
-        ],
-        right: [
-          (rightBB[1] - leftBB[1]) / 2 - sepDiff,
-          (Math.min(leftBB[2], rightBB[2]) + Math.max(leftBB[3], rightBB[3])) / 2,
-          (Math.min(leftBB[4], rightBB[4]) + Math.max(leftBB[5], rightBB[5])) / 2,
-        ],
+        left: [(rightBB[1] - leftBB[1]) / 2 + sepDiff, centerY, centerZ],
+        right: [(rightBB[1] - leftBB[1]) / 2 - sepDiff, centerY, centerZ],
+        center: [centerBB ? (centerBB[0] + centerBB[1] + rightBB[1] - leftBB[1]) / 2 : 0, centerY, centerZ],
       },
       right: {
         right: [(rightBB[0] + rightBB[1]) / 2, (rightBB[2] + rightBB[3]) / 2, (rightBB[4] + rightBB[5]) / 2],
@@ -1583,10 +1588,12 @@ export function fullEstimatedSize(geo: FullGeometry | undefined): Full<[number,
   } else {
     const [lx1, lx2, ly1, ly2, lz1, lz2] = estimatedBB(geo.left)
     const [rx1, rx2, ry1, ry2, rz1, rz2] = estimatedBB(geo.right)
-    const sep = VIEW_SEPARATION - (rx1 + lx1)
+    const [cx1, cx2, cy1, cy2, cz1, cz2] = geo.center ? estimatedBB(geo.center) : [0, 0, Infinity, -Infinity, Infinity, -Infinity]
+    let sep = VIEW_SEPARATION - (rx1 + lx1)
+    if (geo.center) sep += VIEW_SEPARATION + cx2 - cx1 // Extra width for center cluster
     return {
       left: [lx2 - lx1, ly2 - ly1, lz2 - lz1],
-      both: [sep + rx2 + lx2, Math.max(ly2, ry2) - Math.min(ly1, ry1), Math.max(lz2, rz2) - Math.min(lz1, rz1)],
+      both: [sep + rx2 + lx2, Math.max(ly2, ry2, cy2) - Math.min(ly1, ry1, cy1), Math.max(lz2, rz2, cz2) - Math.min(lz1, rz1, cz1)],
       right: [rx2 - rx1, ry2 - ry1, rz2 - rz1],
     }
   }
diff --git a/src/lib/worker/util.ts b/src/lib/worker/util.ts
index ad6a5f5e..54fe430b 100644
--- a/src/lib/worker/util.ts
+++ b/src/lib/worker/util.ts
@@ -1,6 +1,8 @@
-export function match<A extends string | number, R>(x: A, cases: Record<A, R>, fallback?: R) {
+export function match<A extends string | number, R>(x: A, cases: Record<A, R>): R
+export function match<A extends string | number, R>(x: A, cases: Partial<Record<A, R>>, fallback: R): R
+export function match<A extends string | number, R>(x: A, cases: Partial<Record<A, R>>, fallback?: R): R {
   if (cases.hasOwnProperty(x)) {
-    return cases[x]
+    return cases[x]!
   }
   if (typeof fallback === 'undefined') throw new Error(`${x} does not match one of ${Object.keys(cases)}`)
   return fallback
diff --git a/src/proto/cosmos.proto b/src/proto/cosmos.proto
index ea4515dd..3643f528 100644
--- a/src/proto/cosmos.proto
+++ b/src/proto/cosmos.proto
@@ -74,6 +74,7 @@ message KeyboardExtra {
   repeated uint32 foot_indices = 20;
   optional uint32 foot_diameter = 21;
   optional uint32 plate_art = 22;
+  optional int32 connector_center_index = 23;
 }
 
 message Curvature {
diff --git a/src/proto/cosmosStructs.ts b/src/proto/cosmosStructs.ts
index 1b776cac..e9d595e9 100644
--- a/src/proto/cosmosStructs.ts
+++ b/src/proto/cosmosStructs.ts
@@ -74,7 +74,7 @@ enumeration('SCREW_TYPE', ['screw insert', 'tapered screw insert', 'expanding sc
 enumeration('SCREW_SIZE', ['M3', 'M4', '#4-40', '#6-32'])
 
 enumeration('CLUSTER_TYPE', ['matrix', 'sphere'])
-enumeration('CLUSTER_NAME', ['fingers', 'thumbs'])
+enumeration('CLUSTER_NAME', ['fingers', 'thumbs', 'center'])
 enumeration('CLUSTER_SIDE', ['right', 'left'])
 
 enumeration('MICROCONTROLLER_NAME', [
diff --git a/src/routes/beta/App.svelte b/src/routes/beta/App.svelte
index 5bfaea05..9bd03e9a 100644
--- a/src/routes/beta/App.svelte
+++ b/src/routes/beta/App.svelte
@@ -39,6 +39,7 @@
     type Cuttleform,
     type FullCenter,
     type FullCuttleform,
+    type KeyboardSide,
   } from '$lib/worker/config'
   import { checkConfig, type ConfErrors, isRenderable, isWarning, salientError } from '$lib/worker/check'
   import VisualEditor2 from './lib/editor/VisualEditor2.svelte'
@@ -251,6 +252,13 @@
             plate: c.right.plate ? { ...c.right.plate } : undefined,
           }
         : undefined,
+      center: c.center
+        ? {
+            ...c.center,
+            shell: { ...c.center.shell },
+            plate: c.center.plate ? { ...c.center.plate } : undefined,
+          }
+        : undefined,
       unibody: c.unibody
         ? {
             ...c.unibody,
@@ -279,12 +287,13 @@
       ...new Set([
         ...areDifferent(c1.left, c2.left),
         ...areDifferent(c1.right, c2.right),
+        ...areDifferent(c1.center, c2.center),
         ...areDifferent(c1.unibody, c2.unibody),
       ]),
     ]
   }
 
-  const calcOtherPromises = (conf: Cuttleform, side: 'left' | 'right' | 'unibody') => ({
+  const calcOtherPromises = (conf: Cuttleform, side: KeyboardSide) => ({
     intersectionsPromise: pool.execute(
       (w) => w.intersections(conf, side) as Promise<ConfErrors>,
       'Intersections'
@@ -446,10 +455,8 @@
           }
           // size = boundingSize([...keyBufs!, webBuf!])
         })
-        if (kbdNames.includes('right')) delete meshes.unibody
-        else {
-          delete meshes.left
-          delete meshes.right
+        for (const key of objKeys(meshes)) {
+          if (!kbdNames.includes(key)) delete meshes[key]
         }
       }
 
@@ -722,7 +729,7 @@
                   class:selected={$view == 'left'}><Icon name="kb-left" /></button
                 >
                 <button
-                  title="View Both Sides"
+                  title="View All Sides"
                   class="basicbutton px-2"
                   on:click={() => ($view = 'both')}
                   class:selected={$view == 'both'}><Icon name="kbs" /></button
diff --git a/src/routes/beta/lib/ConfError.svelte b/src/routes/beta/lib/ConfError.svelte
index b7488540..4f18eaac 100644
--- a/src/routes/beta/lib/ConfError.svelte
+++ b/src/routes/beta/lib/ConfError.svelte
@@ -22,7 +22,7 @@
   function fixUnseparated() {
     protoConfig.update((p) => {
       const trsfs: Trsf[] = []
-      const sides: ('left' | 'right')[] = []
+      const sides: ('left' | 'right' | 'center')[] = []
       const cpts = mapKeys(p, (k, col, c) => {
         const trsf = cosmosKeyPosition(k, col, c, p).evaluate({ flat: true })
         trsfs.push(trsf)
@@ -112,7 +112,7 @@
   {:else if err.type == 'nokeys'}
     <p class="mb-2">
       You silly goose! You can't make a keyboard without keys. <br />That's like riding a snowboard
-      without snow.
+      without snow. (side={err.side})
       <button on:click={() => window.history.back()} class="underline">Undo.</button>
     </p>
   {:else if err.type == 'missing'}
diff --git a/src/routes/beta/lib/dialogs/AssemblyView.svelte b/src/routes/beta/lib/dialogs/AssemblyView.svelte
index cccd5083..c24e9f82 100644
--- a/src/routes/beta/lib/dialogs/AssemblyView.svelte
+++ b/src/routes/beta/lib/dialogs/AssemblyView.svelte
@@ -3,7 +3,7 @@
   import { mdiChevronLeft, mdiChevronRight, mdiInformationOutline } from '@mdi/js'
   import Icon from '$lib/presentation/Icon.svelte'
   import type { FullGeometry, KeyboardMeshes } from '../viewers/viewer3dHelpers'
-  import type { Center } from '$lib/worker/config'
+  import type { Center, KeyboardSide } from '$lib/worker/config'
   import * as THREE from 'three'
   import { renderedModelsAsScene } from '../modelGLTF'
   import { SORTED_VENDORS } from '@pro/assemblyService'
@@ -12,7 +12,7 @@
   import Dialog from '$lib/presentation/Dialog.svelte'
 
   export let center: Center
-  export let meshes: ['left' | 'right' | 'unibody', KeyboardMeshes][]
+  export let meshes: [KeyboardSide, KeyboardMeshes][]
   export let geometry: FullGeometry
   export let size: [number, number, number]
 
diff --git a/src/routes/beta/lib/dialogs/DownloadDialog.svelte b/src/routes/beta/lib/dialogs/DownloadDialog.svelte
index 319a400b..58d91f58 100644
--- a/src/routes/beta/lib/dialogs/DownloadDialog.svelte
+++ b/src/routes/beta/lib/dialogs/DownloadDialog.svelte
@@ -8,7 +8,12 @@
     noStitch,
   } from '$lib/store'
   import { isPro } from '$lib/worker/check'
-  import { newFullGeometry, setBottomZ, type FullCuttleform } from '$lib/worker/config'
+  import {
+    newFullGeometry,
+    setBottomZ,
+    type FullCuttleform,
+    type KeyboardSide,
+  } from '$lib/worker/config'
   import Dialog from '$lib/presentation/Dialog.svelte'
   import * as flags from '$lib/flags'
   import { createEventDispatcher } from 'svelte'
@@ -44,7 +49,7 @@
   const defaultEmail = lastUser.success && lastUser.method == 'Email' ? lastUser.user.login : ''
   console.log('defaultEmail', defaultEmail, lastUser)
 
-  function downloadSTEP(side: 'left' | 'right' | 'unibody') {
+  function downloadSTEP(side: KeyboardSide) {
     numDownloaded += 1
     if (!config) {
       generatingError = new Error('Configuration has not yet been evaluated')
@@ -78,7 +83,7 @@
       )
   }
 
-  function downloadSTL(model: string, side: 'left' | 'right' | 'unibody' | 'test') {
+  function downloadSTL(model: string, side: KeyboardSide | 'test') {
     numDownloaded += 1
     if (!config) {
       generatingError = new Error('Configuration has not yet been evaluated')
@@ -140,7 +145,7 @@
     return new Blob([contents], { type: blob.type })
   }
 
-  async function downloadGLB(side: 'left' | 'right' | 'unibody') {
+  async function downloadGLB(side: KeyboardSide) {
     numDownloaded += 1
     generatingGLB = true
     const scene = await modelAsScene(pool, newFullGeometry(config), side)
@@ -151,20 +156,26 @@
     generatingGLB = false
   }
 
-  function iconPath(kbdName: 'left' | 'right' | 'unibody') {
+  const centerIcon =
+    'M8.5 0C7.4 0 6.5.7 6.2 1.6c-.2-.1-.5-.1-.7-.1C4.1 1.5 3 2.6 3 4v.5c-.2 0-.3 0-.5 0C1.1 4.5 0 5.6 0 7v9c0 4.4 3.6 8 8 8 1.4 0 2.8-.4 4-1 1.2.6 2.6 1 4 1 4.4 0 8-3.6 8-8V7c0-1.4-1.1-2.5-2.5-2.5-.2 0-.3 0-.5 0V4c0-1.4-1.1-2.5-2.5-2.5-.2 0-.5 0-.7.1C17.5.7 16.6 0 15.5 0 14.3 0 13.3.9 13 2.1c-.1-.1-.3-.1-.5-.1s-.3 0-.5 0-.3 0-.5 0-.4 0-.5.1C10.8.9 9.7 0 8.5 0Zm0 2c.3 0 .5.2.5.5V9.8c-.1 0-.2 0-.2-.1 0 0 0 0 0 0-.4-.1-.6.1-.8.4V2.5c0-.3.2-.5.5-.5Zm7 0c.3 0 .5.2.5.5v7.6c-.2-.3-.4-.5-.8-.4 0 .1-.1.1-.2.1V2.5c0-.3.2-.5.5-.5ZM5.5 3.5c.3 0 .5.2.5.5v8H7.5c-.2 2.2.2 5.4.7 6.7.5 1.1 1.1 2.1 2 2.9-.7.3-1.4.4-2.2.4-3 0-5.4-2.1-5.9-5-.1-.3-.1-.6-.1-1V7c0-.3.2-.5.5-.5s.5.2.5.5v5H5V4c0-.3.2-.5.5-.5Zm13 0c.3 0 .5.2.5.5v8h2V7c0-.3.2-.5.5-.5s.5.2.5.5v9c0 3.3-2.7 6-6 6-.7 0-1.5-.1-2.2-.4.9-.8 1.5-1.8 2-2.9.5-.9.7-3.4.6-5.5 0-.4 0-.8 0-1.2H18V4c0-.3.2-.5.5-.5Z'
+
+  function iconPath(kbdName: KeyboardSide) {
     if (kbdName == 'left') return mdiHandBackLeft
     if (kbdName == 'right') return mdiHandBackRight
+    if (kbdName == 'center') return centerIcon
     return mdiKeyboard
   }
 
-  function kbdName(kbdName: 'left' | 'right' | 'unibody', name = '') {
+  function kbdName(kbdName: KeyboardSide, name = '') {
     if (name) {
       if (kbdName == 'left') return 'L / ' + name
       if (kbdName == 'right') return 'R / ' + name
+      if (kbdName == 'center') return 'C / ' + name
       return name
     }
     if (kbdName == 'left') return 'Left'
     if (kbdName == 'right') return 'Right'
+    if (kbdName == 'center') return 'Center'
     return 'Unibody'
   }
 
@@ -184,7 +195,8 @@
     $emailMinimized = Date.now()
   }
 
-  $: configKeys = objKeys(config).sort()
+  const order = (s: string) => (s == 'center' ? Infinity : s.charCodeAt(0))
+  $: configKeys = objKeys(config).sort((a, b) => order(a) - order(b))
 </script>
 
 <Dialog on:close>
@@ -270,7 +282,7 @@
       <div class="columns-2">
         <div class="break-inside-avoid">
           <h3 class="mb-2 text-lg semibold text-black dark:text-white">Case/Shell</h3>
-          <div class="inline-flex items-center gap-2">
+          <div class="inline-flex items-center gap-2 flex-wrap justify-center">
             {#each configKeys as kbd}
               <button class="button flex items-center gap-2" on:click={() => downloadSTL('model', kbd)}
                 ><Icon path={iconPath(kbd)} />{kbdName(kbd)}</button
@@ -281,7 +293,7 @@
         <div class="break-inside-avoid">
           <h3 class="mb-2 mt-4 text-lg semibold text-black dark:text-white">Plate</h3>
           {#if Object.values(config).some((c) => c.shell.type == 'tilt' || c.shell.type == 'stilts')}
-            <div class="inline-flex items-center gap-2">
+            <div class="inline-flex items-center gap-2 flex-wrap justify-center">
               {#each configKeys as kbd}
                 <button
                   class="button flex items-center gap-2"
@@ -290,7 +302,7 @@
                 >
               {/each}
             </div>
-            <div class="inline-flex items-center gap-2 mt-2">
+            <div class="inline-flex items-center gap-2 flex-wrap justify-center mt-2">
               {#each configKeys as kbd}
                 <button
                   class="button flex items-center gap-2"
@@ -303,7 +315,7 @@
               Download both the Top and Bot models.
             </div>
           {:else}
-            <div class="inline-flex items-center gap-2">
+            <div class="inline-flex items-center gap-2 flex-wrap justify-center">
               {#each configKeys as kbd}
                 <button class="button flex items-center gap-2" on:click={() => downloadSTL('plate', kbd)}
                   ><Icon path={iconPath(kbd)} />{kbdName(kbd)}</button
@@ -315,7 +327,7 @@
         {#if Object.values(config).some((c) => c.microcontroller)}
           <div class="break-inside-avoid">
             <h3 class="mb-2 mt-4 text-lg semibold text-black dark:text-white">Microcontroller Holder</h3>
-            <div class="inline-flex items-center gap-2">
+            <div class="inline-flex items-center gap-2 flex-wrap justify-center">
               {#each configKeys as kbd}
                 <button
                   class="button flex items-center gap-2"
@@ -331,7 +343,7 @@
             <h3 class="mb-2 mt-4 text-lg semibold text-black dark:text-white">Wrist Rest</h3>
             {#if $user.success && $user.sponsor}
               {#if Object.values(config).some((c) => c.wristRestRight)}
-                <div class="inline-flex items-center gap-2">
+                <div class="inline-flex items-center gap-2 flex-wrap justify-center">
                   {#each configKeys as kbd}
                     <button
                       class="button flex items-center gap-2"
@@ -362,7 +374,7 @@
           href="docs/cad/">[Importing Guide]</a
         >
       </p>
-      <div class="inline-flex items-center gap-2">
+      <div class="inline-flex items-center gap-2 flex-wrap justify-center">
         {#each configKeys as kbd}
           <button class="button flex items-center gap-2" on:click={() => downloadSTEP(kbd)}>
             <Icon path={iconPath(kbd)} />{kbdName(kbd)}
@@ -392,7 +404,7 @@
         <div class="flex items-center justify-center mb-2 gap-1">
           <!-- svelte-ignore a11y-label-has-associated-control-->
         </div>
-        <div class="inline-flex items-center gap-2">
+        <div class="inline-flex items-center gap-2 flex-wrap justify-center">
           {#each configKeys as kbd}
             <button class="button flex items-center gap-2" on:click={() => downloadGLB(kbd)}>
               <Icon path={iconPath(kbd)} />{kbdName(kbd)}
diff --git a/src/routes/beta/lib/dialogs/URLView.svelte b/src/routes/beta/lib/dialogs/URLView.svelte
index f3f66bc9..42a22fa5 100644
--- a/src/routes/beta/lib/dialogs/URLView.svelte
+++ b/src/routes/beta/lib/dialogs/URLView.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
   import { protoConfig } from '$lib/store'
   import { serialize } from '../serialize'
-  import type { CosmosKeyboard } from '$lib/worker/config.cosmos'
+  import type { CosmosCluster, CosmosKeyboard } from '$lib/worker/config.cosmos'
   import { encodeCosmosConfig, serializeCosmosConfig } from '$lib/worker/config.serialize'
   import { Cluster, type Keyboard } from '../../../../../target/proto/cosmos'
 
@@ -82,6 +82,12 @@
     return allParts
   }
 
+  function clusterLabel(cluster: CosmosCluster): string {
+    if (cluster.name == 'center' || cluster.side == 'center') return 'Center Keys'
+    const side = cluster.side == 'left' ? 'Left' : 'Right'
+    return cluster.name == 'thumbs' ? `${side} Thumb Keys` : `${side} Upper Keys`
+  }
+
   function calcParts(mode: string, url: string, conf: CosmosKeyboard) {
     if (mode == 'advanced') {
       if (!url) return []
@@ -98,15 +104,11 @@
     const rawHash = Uint8Array.from(window.atob(url), (c) => c.charCodeAt(0))
 
     const keeb = encodeCosmosConfig(conf)
-    const parts: Part[] = [
-      createPartCluster(rawHash, 'Right Upper Keys', keeb.cluster[0]),
-      createPartCluster(rawHash, 'Right Thumb Keys', keeb.cluster[1]),
-    ]
-    let i = 2
-    if (conf.clusters.find((c) => c.side == 'left' && c.name == 'fingers'))
-      parts.push(createPartCluster(rawHash, 'Left Upper Keys', keeb.cluster[i++]))
-    if (conf.clusters.find((c) => c.side == 'left' && c.name == 'thumbs'))
-      parts.push(createPartCluster(rawHash, 'Left Thumb Keys', keeb.cluster[i++]))
+    // encodeCosmosConfig maps conf.clusters 1:1 onto keeb.cluster, so the
+    // indices line up regardless of how many sides/center clusters exist.
+    const parts: Part[] = conf.clusters.map((cluster, i) =>
+      createPartCluster(rawHash, clusterLabel(cluster), keeb.cluster[i])
+    )
     parts.push(
       createPart(rawHash, 'Keyboard', {
         ...keeb,
diff --git a/src/routes/beta/lib/editor/PeaConfig.svelte b/src/routes/beta/lib/editor/PeaConfig.svelte
index ba53b4a3..7f583825 100644
--- a/src/routes/beta/lib/editor/PeaConfig.svelte
+++ b/src/routes/beta/lib/editor/PeaConfig.svelte
@@ -87,6 +87,13 @@
 <p class="mt-4 mb-2">Successfully made the matrix!</p>
 <p class="mb-2">Now you can download code for your microcontroller.</p>
 
+{#if !!config.center}
+  <InfoBox>
+    Firmware will not be generated for the center cluster. The center cluster's keys must be wired
+    manually.
+  </InfoBox>
+{/if}
+
 <div class="mt-8 text-gray-500 dark:text-gray-200" class:mb-4={!truncated}>
   Keyboard / File Name: <input class="input px-2" bind:value={$modelName} />
 </div>
diff --git a/src/routes/beta/lib/editor/VisualEditor2.svelte b/src/routes/beta/lib/editor/VisualEditor2.svelte
index ac9ad5f3..2a2e1149 100644
--- a/src/routes/beta/lib/editor/VisualEditor2.svelte
+++ b/src/routes/beta/lib/editor/VisualEditor2.svelte
@@ -28,6 +28,8 @@
     fromCosmosConfig,
     mirrorCluster,
     partVariant,
+    sortClusters,
+    toCosmosConfig,
     type ConnectorMaybeCustom,
     type CosmosKeyboard,
     type PartType,
@@ -46,21 +48,24 @@
     connectorsString,
     getNKeys,
     getSize,
-    getThumbN,
+    getPresetN,
     hasInnerCol,
     hasKey,
     hasOuterCol,
     isFnKey,
     isNumKey,
-    isThumb,
+    isPreset,
     setClusterAngle,
+    setClusterSeparationFromCenter,
     setClusterSeparation,
     setClusterSize,
-    setThumbCluster,
     toggleFnRow,
     toggleInnerCol,
     toggleNumRow,
     toggleOuterCol,
+    setPreset,
+    type ThumbPreset,
+    type CenterPreset,
   } from './visualEditorHelpers'
   import {
     DEFAULT_LAYOUT,
@@ -96,6 +101,9 @@
   $: protoConfig.set(cosmosConf)
   $: conf = fromCosmosConfig($protoConfig)
 
+  const UNIBODY_SEPARATION = 30
+  const UNIBODY_CENTER_SEPARATION = 5
+
   const dispatch = createEventDispatcher()
 
   function goAdvanced() {
@@ -296,18 +304,33 @@
     })
   }
 
+  function ensureClusters(c: CosmosKeyboard) {
+    const hasFingers = c.clusters.find((cl) => cl.side == 'left' && cl.name == 'fingers')
+    const hasThumbs = c.clusters.find((cl) => cl.side == 'left' && cl.name == 'thumbs')
+    if (!hasFingers) addNewCluster(c, 'fingers')
+    if (!hasThumbs) addNewCluster(c, 'thumbs')
+    return !hasFingers || !hasThumbs
+  }
+
+  function addNewCluster(c: CosmosKeyboard, cluster: 'fingers' | 'thumbs') {
+    const newCluster = mirrorCluster(
+      c.clusters.find((cl) => cl.side == 'right' && cl.name == cluster)!,
+      c
+    )
+    c.clusters.splice(cluster == 'fingers' ? 2 : 3, 0, newCluster)
+    sortClusters(c.clusters)
+  }
+
   function editJointlySeparately(cluster: 'fingers' | 'thumbs') {
     protoConfig.update((proto) => {
       const secondCluster = proto.clusters.find((c) => c.side == 'left' && c.name == cluster)
       if (secondCluster) {
-        if (confirm('This will overwrite the left side of the keyboard with the right. Continue?'))
+        if (confirm('This will overwrite the left side of the keyboard with the right. Continue?')) {
           proto.clusters.splice(proto.clusters.indexOf(secondCluster), 1)
+          sortClusters(proto.clusters)
+        }
       } else {
-        proto.clusters.splice(
-          cluster == 'fingers' ? 2 : 3,
-          0,
-          mirrorCluster(proto.clusters.find((c) => c.side == 'right' && c.name == cluster)!, proto)
-        )
+        addNewCluster(proto, cluster)
       }
       return proto
     })
@@ -405,13 +428,23 @@
     }
   }
 
-  function setThumb(
-    type: 'carbonfet' | 'manuform' | 'orbyl' | 'curved',
-    side: 'left' | 'right',
-    e?: Event
-  ) {
+  function setThumb(type: ThumbPreset, side: 'left' | 'right', e?: Event) {
     const n = e ? Number((e.target as HTMLInputElement).value) : undefined
-    protoConfig.update((p) => setThumbCluster(p, type, side, n))
+    protoConfig.update((p) => setPreset(p, 'thumbs', type, side, n))
+  }
+
+  function setCenter(which: CenterPreset, e: Event) {
+    const n = Number((e.target as HTMLInputElement).value)
+    protoConfig.update((p) => setPreset(p, 'center', which, 'center', n))
+  }
+
+  function centerWithUnibody(p: CosmosKeyboard, which: CenterPreset) {
+    p = setPreset(p, 'center', which, 'center')
+    if (p.unibody) {
+      setClusterSeparationFromCenter(p, UNIBODY_CENTER_SEPARATION, 'left')
+      setClusterSeparationFromCenter(p, UNIBODY_CENTER_SEPARATION, 'right')
+    }
+    return p
   }
 
   function setNoThumb(side: 'left' | 'right') {
@@ -421,17 +454,34 @@
     })
   }
 
+  function setNoCenter() {
+    protoConfig.update((p) => {
+      p.clusters = p.clusters.filter((cl) => cl.side !== 'center')
+      if (p.unibody) setClusterSeparation(p, UNIBODY_SEPARATION)
+      return p
+    })
+  }
+
   function setUnibody(ev: Event) {
     protoConfig.update((proto) => {
       proto.unibody = (ev.target as HTMLInputElement).checked
       if (proto.unibody) {
-        setClusterSeparation(proto, 30)
+        const centerCluster = proto.clusters.find((c) => c.side == 'center' && c.clusters.length)
+        if (centerCluster) {
+          // Set center cluster to x=0 so it's centered
+          const [_cx, cy, cz] = decodeTuple(centerCluster.position ?? 0n)
+          centerCluster.position = encodeTuple([0, cy, cz])
+          setClusterSeparationFromCenter(proto, UNIBODY_CENTER_SEPARATION, 'left')
+          setClusterSeparationFromCenter(proto, UNIBODY_CENTER_SEPARATION, 'right')
+        } else {
+          setClusterSeparation(proto, UNIBODY_SEPARATION)
+        }
         // Double the number of screw indices
         proto.screwIndices = proto.screwIndices.concat(new Array(proto.screwIndices.length).fill(-1))
       } else {
         // Move everything so wrist rest goes to position 10
         const wristRestMovement = 10 - decodeTuple(proto.wristRestPosition)[0] / 10
-        setClusterSeparation(proto, clusterSeparation(proto) + wristRestMovement * 2)
+        setClusterSeparation(proto, clusterSeparation(proto, 'left', 'right') + wristRestMovement * 2)
         // Halve the number of screw indices
         proto.screwIndices = proto.screwIndices.slice(0, Math.ceil(proto.screwIndices.length / 2))
       }
@@ -470,10 +520,13 @@
   $: leftThumbCluster = $protoConfig.clusters.find((c) => c.name == 'thumbs' && c.side == 'left')
   $: rightFingersCl = $protoConfig.clusters.find((c) => c.name == 'fingers' && c.side == 'right')!
   $: leftFingersCl = $protoConfig.clusters.find((c) => c.name == 'fingers' && c.side == 'left')
+  $: centerCl = $protoConfig.clusters.find((c) => c.side == 'center')
   $: tempFingersCluster = $tempConfig.clusters.find((c) => c.name == 'fingers')!
 
-  $: whichRight = getThumbN($protoConfig, 'right')
-  $: whichLeft = getThumbN($protoConfig, 'left')
+  $: whichRight = getPresetN($protoConfig, 'thumbs', 'right')
+  $: whichLeft = getPresetN($protoConfig, 'thumbs', 'left')
+  $: whichCenter = getPresetN($protoConfig, 'center', 'center')
+  $: hasCenterCl = $protoConfig.clusters.some((cl) => cl.side === 'center' && cl.clusters.length > 0)
 
   const rotationStore = new TupleStore(-1n, 45, true)
   const [rotationX, rotationY, rotationZ, _] = rotationStore.components()
@@ -489,10 +542,23 @@
   wrPositionStore.tuple.subscribe((t) => updateWrPosition(t))
   $: wrPositionStore.update($protoConfig.wristRestPosition || 0n)
 
-  $: clusterSep = clusterSeparation($tempConfig)
+  $: clusterSep = clusterSeparation($tempConfig, 'left', 'right')
   const setClusterSep = (ev: CustomEvent) =>
     protoConfig.update((proto) => setClusterSeparation(proto, ev.detail))
 
+  $: clusterLeftSep = clusterSeparation($tempConfig, 'left', 'center')
+  $: clusterRightSep = clusterSeparation($tempConfig, 'center', 'right')
+  const setClusterLeftSep = (ev: CustomEvent) =>
+    protoConfig.update((proto) => {
+      ensureClusters(proto)
+      return setClusterSeparationFromCenter(proto, ev.detail, 'left')
+    })
+  const setClusterRightSep = (ev: CustomEvent) =>
+    protoConfig.update((proto) => {
+      ensureClusters(proto)
+      return setClusterSeparationFromCenter(proto, ev.detail, 'right')
+    })
+
   $: clusterAng = clusterAngle($tempConfig)
   const setClusterAng = (ev: CustomEvent) =>
     protoConfig.update((proto) => setClusterAngle(proto, ev.detail))
@@ -759,22 +825,22 @@
     <Preset
       name="Manuform"
       on:click={() => setThumb('manuform', 'left')}
-      selected={isThumb($protoConfig, 'manuform', 'left')}
+      selected={isPreset($protoConfig, 'thumbs', 'manuform', 'left')}
     />
     <Preset
       name="Carbonfet"
       on:click={() => setThumb('carbonfet', 'left')}
-      selected={isThumb($protoConfig, 'carbonfet', 'left')}
+      selected={isPreset($protoConfig, 'thumbs', 'carbonfet', 'left')}
     />
     <Preset
       name="Orbyl"
       on:click={() => setThumb('orbyl', 'left')}
-      selected={isThumb($protoConfig, 'orbyl', 'left')}
+      selected={isPreset($protoConfig, 'thumbs', 'orbyl', 'left')}
     />
     <Preset
       name="Curved"
       on:click={() => setThumb('curved', 'left')}
-      selected={isThumb($protoConfig, 'curved', 'left')}
+      selected={isPreset($protoConfig, 'thumbs', 'curved', 'left')}
     />
     <Preset on:click={() => setNoThumb('left')} selected={leftThumbCluster?.clusters.length == 0}
       ><span class="relative top-[-0.1em]">&empty;</span></Preset
@@ -821,22 +887,22 @@
   <Preset
     name="Manuform"
     on:click={() => setThumb('manuform', 'right')}
-    selected={isThumb($protoConfig, 'manuform', 'right')}
+    selected={isPreset($protoConfig, 'thumbs', 'manuform', 'right')}
   />
   <Preset
     name="Carbonfet"
     on:click={() => setThumb('carbonfet', 'right')}
-    selected={isThumb($protoConfig, 'carbonfet', 'right')}
+    selected={isPreset($protoConfig, 'thumbs', 'carbonfet', 'right')}
   />
   <Preset
     name="Orbyl"
     on:click={() => setThumb('orbyl', 'right')}
-    selected={isThumb($protoConfig, 'orbyl', 'right')}
+    selected={isPreset($protoConfig, 'thumbs', 'orbyl', 'right')}
   />
   <Preset
     name="Curved"
     on:click={() => setThumb('curved', 'right')}
-    selected={isThumb($protoConfig, 'curved', 'right')}
+    selected={isPreset($protoConfig, 'thumbs', 'curved', 'right')}
   />
   <Preset on:click={() => setNoThumb('right')} selected={rightThumbCluster?.clusters.length == 0}
     ><span class="relative top-[-0.1em]">&empty;</span></Preset
@@ -873,6 +939,53 @@
     </Field>
   {/if}
 </Section>
+<Section name="Center Cluster">
+  <Preset on:click={setNoCenter} selected={!centerCl || centerCl.clusters.length == 0}
+    ><span class="relative top-[-0.1em]">&empty;</span></Preset
+  >
+  <Preset
+    name="Display"
+    on:click={() => protoConfig.update((p) => centerWithUnibody(p, 'display'))}
+    selected={isPreset($protoConfig, 'center', 'display', 'center')}
+  />
+  <Preset
+    name="Trackball"
+    on:click={() => protoConfig.update((p) => centerWithUnibody(p, 'trackball'))}
+    selected={isPreset($protoConfig, 'center', 'trackball', 'center')}
+  />
+  {#if whichCenter}
+    {@const which = whichCenter.which}
+    <Field name="Number of Keys" icon="numeric">
+      <Select value={whichCenter.n} on:change={(e) => setCenter(which, e)}>
+        {#each whichCenter.options.toReversed() as opt}<option value={opt}>{opt}</option>{/each}
+      </Select>
+    </Field>
+  {/if}
+  {#if centerCl && centerCl.clusters.length > 0}
+    <Field name="Row's Curvature" plusminus icon="row-curve">
+      <AngleInput bind:value={centerCl.curvature.curvatureA} />
+    </Field>
+    <Field name="Column's Curvature" plusminus icon="column-curve">
+      <AngleInput bind:value={centerCl.curvature.curvatureB} />
+    </Field>
+    {#if !basic}
+      <Field name="Horizontal (X) Spacing" icon="expand-horizontal">
+        <DecimalInputInherit
+          bind:value={centerCl.curvature.horizontalSpacing}
+          inherit={$protoConfig.curvature.horizontalSpacing}
+          units="mm"
+        />
+      </Field>
+      <Field name="Vertical (Y) Spacing" icon="expand-vertical">
+        <DecimalInputInherit
+          bind:value={centerCl.curvature.verticalSpacing}
+          inherit={$protoConfig.curvature.horizontalSpacing}
+          units="mm"
+        />
+      </Field>
+    {/if}
+  {/if}
+</Section>
 <!--
 <Section name="Thumb Cluster">
   <svelte:fragment slot="preset">
@@ -1164,9 +1277,19 @@
         <DecimalInput bind:value={$protoConfig.connectorLeftIndex} class="w-[5.2rem]" />
         <DecimalInput bind:value={$protoConfig.connectorRightIndex} class="w-[5.2rem]" />
       </Field>
+      {#if hasCenterCl}
+        <Field
+          name="Connector Index (C)"
+          help="Position of the microcontroller and connector on the center piece, expressed as a wall index.<br>Currently, it is {attempt(
+            () => geometry.center?.connectorIndex
+          )} (0–{geometry.center?.allWallCriticalPoints().length})."
+        >
+          <DecimalInput bind:value={$protoConfig.connectorCenterIndex} />
+        </Field>
+      {/if}
     {/if}
   {/if}
-  {#if $protoConfig.connectorRightIndex != -1 || (!$protoConfig.unibody && $protoConfig.connectorLeftIndex != -1)}
+  {#if $protoConfig.connectorRightIndex != -1 || (!$protoConfig.unibody && $protoConfig.connectorLeftIndex != -1) || (hasCenterCl && $protoConfig.connectorCenterIndex != -1)}
     <InfoBox>
       The microcontroller and connector are manually placed in this model. Set Advanced &rarr; Connector
       Index to -1 to automatically place them.
@@ -1412,9 +1535,19 @@
     <Checkbox value={$protoConfig.unibody} on:change={setUnibody} />
   </Field>
   {#if $protoConfig.unibody}
-    <Field name="Unibody Separation" help="Minimum distance between the left and right clusters">
-      <DecimalInput value={clusterSep} on:change={setClusterSep} units="mm" />
-    </Field>
+    {#if hasCenterCl}
+      <Field
+        name="Unibody Separation (L/R)"
+        help="Distance from the left half to center, and from center to the right half"
+      >
+        <DecimalInput value={clusterLeftSep} on:change={setClusterLeftSep} class="w-[5.2rem]" />
+        <DecimalInput value={clusterRightSep} on:change={setClusterRightSep} class="w-[5.2rem]" />
+      </Field>
+    {:else}
+      <Field name="Unibody Separation" help="Minimum distance between the left and right clusters">
+        <DecimalInput value={clusterSep} on:change={setClusterSep} units="mm" />
+      </Field>
+    {/if}
     <Field name="Unibody Angle">
       <AngleInput value={clusterAng} on:change={setClusterAng} />
     </Field>
diff --git a/src/routes/beta/lib/editor/toCode.ts b/src/routes/beta/lib/editor/toCode.ts
index 33adc556..831adb4f 100644
--- a/src/routes/beta/lib/editor/toCode.ts
+++ b/src/routes/beta/lib/editor/toCode.ts
@@ -66,16 +66,19 @@ export function toCode(proto: CosmosKeyboard) {
   const fingerDefinitions: string[] = []
   const fingerReferences: string[] = []
   const screwStuff: string[] = []
+
   for (const [name, kbd] of objEntries(cosmosConf)) {
+    const sides = name == 'center' ? ['center'] : ['fingers', 'thumbs']
+
     fingerReferences.push(
       `  ${name}: {`,
       '    ...options,',
       ...(kbd!.connectorIndex != -1 ? [`    connectorIndex: ${kbd!.connectorIndex},`] : []),
-      `    keys: [...fingers${capitalize(name)}, ...thumbs${capitalize(name)}],`,
+      `    keys: [${sides.map(s => '...' + s + capitalize(name)).join(', ')}],`,
       ...(name == 'left' && !proto.mirrorConnectors ? ['    flipConnectors: true'] : []),
       '  },',
     )
-    for (const side of ['fingers', 'thumbs']) {
+    for (const side of sides) {
       const keys = kbd!.keys.filter(k => k.cluster == side)
       fingerDefinitions.push(
         'const ' + side + capitalize(name) + ': Key[] = ' + jsonToCode(keys) + '\n',
diff --git a/src/routes/beta/lib/editor/visualEditorHelpers.ts b/src/routes/beta/lib/editor/visualEditorHelpers.ts
index 306b0763..563d8c1b 100644
--- a/src/routes/beta/lib/editor/visualEditorHelpers.ts
+++ b/src/routes/beta/lib/editor/visualEditorHelpers.ts
@@ -1,6 +1,6 @@
 import { DEFAULT_LAYOUT, flipLetter, rightCells } from '$lib/geometry/layouts'
 import { PART_INFO } from '$lib/geometry/socketsParts'
-import { approximateCosmosThumbOrigin, cosmosFingers, type Cuttleform, decodeTuple, encodeTuple, type FullCuttleform, newGeometry } from '$lib/worker/config'
+import { approximateCosmosThumbOrigin, type Center, cosmosFingers, type Cuttleform, decodeTuple, encodeTuple, type FullCuttleform, type KeyboardSide, newGeometry } from '$lib/worker/config'
 import {
   type ConnectorMaybeCustom,
   type CosmosCluster,
@@ -11,16 +11,53 @@ import {
   mirrorCluster,
   type PartType,
   sideFromCosmosConfig,
+  sortClusters,
   toCosmosConfig,
 } from '$lib/worker/config.cosmos'
 import { decodeCosmosCluster, LETTERS } from '$lib/worker/config.serialize'
 import { estimatedBB } from '$lib/worker/geometry'
 import { Vector } from '$lib/worker/modeling/transformation'
-import { mapObj, objKeys, sum } from '$lib/worker/util'
+import { mapObj, objEntries, objKeys, sum } from '$lib/worker/util'
 import type { Layout } from '$target/cosmosStructs'
 import { Cluster } from '../../../../../target/proto/cosmos'
 import { addColumnInPlace } from '../viewers/viewer3dHelpers'
 
+export type ThumbPreset = 'curved' | 'carbonfet' | 'manuform' | 'orbyl'
+const THUMB_CONFIG: Record<ThumbPreset, { b64: string; n?: number[]; defaultN?: number }> = {
+  curved: {
+    b64:
+      'Ci8SExDAjwJAgICYAkjCmaCVkLwBUEMSFhDApwJAgIDMAkjCmaCVkLwBUIYBWDo4CAoWEhEQwANAgIAgSNCVgN2Q9QNQC1CeAgorEhEQwBtAgID4AUjmmfynkAtQVxIUEMAzQICApANI8JnEtdAwUHRYlQFQfwoYEhMQgD9AkrbtDEj6mejs8PwCUIYBUIICGAIiCgjIARDIARgAIABAy4v8n9AxSK2R3I3BkwY=',
+    n: [2, 3, 4, 5, 6],
+    defaultN: 5,
+  },
+  carbonfet: {
+    b64: 'ChASBhBAIA5AARIEIAVAATgTCiESEQiAMBDAgAJAAUiAgIz9A1ByEgoIgCAQQEABUIUBOAAKHBIPCIAwEEBAAUiAgIz9A1BaEgcIgCAgD0ABOBQYAiIKCMgBEMgBGAAgAEDXicymkDZIqY2AtvGXHA==',
+  },
+  manuform: {
+    b64:
+      'CoMBEhYIgDAQwMACIABAi4XYlhBIjYWAwN0NEhQIgDAQwAMgAECaxJYISI2FgMDdDRISEMAbIABArYXcA0iZiYSe4NwQEhMQwCcgAEDig9jQAUjpk5yXoPAREhIQwDMgAEDP4o84SIOPnJegvRISFBDAPyAAQPCFvJewAUjhncyNwNgSOAAYAiIKCMgBEMgBGAAgAECdjcys8DNIpqngxvCzCA==',
+    n: [2, 3, 4, 6],
+    defaultN: 6,
+  },
+  orbyl: {
+    b64: 'CgoSBRBAUPICOMAMCgsSBhDAgAIgKDioFAoJEgQQQCAoOJAcCgsSBhBAIChAADj4IwoYEhIQQCAAMMgBQICAgA1IgICwrAEwFjgAGAoiCgjIARDIARgAIABA25GknPA3SISPlNageA==',
+  },
+}
+
+export type CenterPreset = 'display' | 'trackball'
+const CENTER_CONFIG: Record<CenterPreset, { b64: string; n?: number[]; defaultN?: number }> = {
+  display: {
+    b64: 'CkwSFggIEDAgEyhkMPQDQIDmkBxIgICQ/QMSGAiRMBDAgAIgAECAvLgMSIC2qqH6B4gBUBILEEAgAECrhbyc8DgSCSAAQKyFvJzwODgAGAQiCgjIARDIARgAIABAgJAX',
+  },
+  trackball: {
+    b64: 'CkcSFgiSMBDAgAIgAECA0JLgH0iA6tKg+gcSFQiWgBIQQCAAQICehugBSICGnqD6BxIJIABAq4Wcv/A4EgkgAECshZy/8Dg4AAoVEhEICBAwIAAoMjCgBkCsBUiEDzgUChUSEQgIEDAgACgyMKAGQKsFSIQPOBMYBCIKCMgBEMgBGAAgAECAkJfwBQ==',
+  },
+}
+
+const decodedClusters = mapObj(THUMB_CONFIG, ({ b64 }) => decodeCosmosCluster(Cluster.fromBinary(Uint8Array.from(atob(b64), c => c.charCodeAt(0)))))
+const mirroredDecodedClusters = mapObj(decodedClusters, c => mirrorCluster(c, undefined))
+const decodedCenterClusters = mapObj(CENTER_CONFIG, ({ b64 }) => decodeCosmosCluster(Cluster.fromBinary(Uint8Array.from(atob(b64), c => c.charCodeAt(0)))))
+
 export function getSize(c: CosmosKeyboard, side: 'left' | 'right') {
   const fingers = c.clusters.find((c) => c.name == 'fingers' && c.side == side)
   if (!fingers) return undefined
@@ -50,9 +87,9 @@ export function setClusterSize(keyboard: CosmosKeyboard, side: 'left' | 'right',
   return keyboard
 }
 
-export function clusterSeparation(c: CosmosKeyboard) {
-  const rightSide = sideFromCosmosConfig(c, 'right', false)
-  const leftSide = sideFromCosmosConfig(c, 'left', false)
+export function clusterSeparation(c: CosmosKeyboard, left: KeyboardSide, right: KeyboardSide) {
+  const rightSide = sideFromCosmosConfig(c, right, false)
+  const leftSide = sideFromCosmosConfig(c, left, false)
   if (!leftSide || !rightSide) return 0
   const rightBB = estimatedBB(newGeometry(rightSide), false, false)
   const leftBB = estimatedBB(newGeometry(leftSide), false, false)
@@ -60,19 +97,34 @@ export function clusterSeparation(c: CosmosKeyboard) {
 }
 
 export function setClusterSeparation(c: CosmosKeyboard, desiredSeparation: number) {
-  const currentSeparation = clusterSeparation(c)
+  const currentSeparation = clusterSeparation(c, 'left', 'right')
   const separationToAdd = (desiredSeparation - currentSeparation) / 2
   for (const cluster of c.clusters) {
+    if (cluster.side === 'center') continue // Center stays put; left/right move outward.
     let [x, y, z] = decodeTuple(cluster.position ?? 0n)
     x += Math.round(10 * (cluster.side == 'left' ? -separationToAdd : separationToAdd))
     cluster.position = encodeTuple([x, y, z])
   }
   let [x, y, z] = decodeTuple(c.wristRestPosition)
-  x += 10 * separationToAdd
+  x += Math.round(10 * separationToAdd)
   c.wristRestPosition = encodeTuple([x, y, z])
   return c
 }
 
+/** Keeps center in place and adjusts the separation between center and one side of the keyboard */
+export function setClusterSeparationFromCenter(c: CosmosKeyboard, desiredGap: number, side: KeyboardSide) {
+  const delta = side == 'left'
+    ? clusterSeparation(c, 'left', 'center') - desiredGap
+    : desiredGap - clusterSeparation(c, 'center', 'right')
+
+  for (const cluster of c.clusters) {
+    if (cluster.side !== side) continue
+    const [x, y, z] = decodeTuple(cluster.position ?? 0n)
+    cluster.position = encodeTuple([x + Math.round(10 * delta), y, z])
+  }
+  return c
+}
+
 export function clusterAngle(c: CosmosKeyboard) {
   const rightFingerCluster = c.clusters.find(c => c.name == 'fingers' && c.side == 'right')!
   const leftFingerCluster = c.clusters.find(c => c.name == 'fingers' && c.side == 'left') || rightFingerCluster
@@ -113,84 +165,10 @@ export function setClusterAngle(c: CosmosKeyboard, desiredAngle: number) {
   return c
 }
 
-// export function setThumbCluster(c: CosmosKeyboard, type: 'carbonfet' | 'manuform' | 'orbyl' | 'curved', side: 'left' | 'right') {
-//   // @ts-ignore
-//   let cc: CuttleformProto = { ...cuttleform.options }
-
-//   if (type == 'manuform') {
-//     cc.thumbCluster = {
-//       oneofKind: 'defaultThumb',
-//       defaultThumb: {
-//         thumbCount: Cuttleform_DefaultThumb_KEY_COUNT.SIX,
-//         encoder: false,
-//         encoderType: ENCODER.EC11,
-//       },
-//     }
-//   } else if (type == 'curved') {
-//     cc.thumbCluster = {
-//       oneofKind: 'curvedThumb',
-//       curvedThumb: {
-//         thumbCount: Cuttleform_CurvedThumb_KEY_COUNT.FIVE,
-//         rowCurve: 0,
-//         columnCurve: 0,
-//         horizontalSpacing: 200,
-//         verticalSpacing: 200,
-//         encoder: false,
-//         encoderType: ENCODER.EC11,
-//       },
-//     }
-//   } else if (type == 'orbyl') {
-//     cc.thumbCluster = {
-//       oneofKind: 'orbylThumb',
-//       orbylThumb: {
-//         curvature: 0,
-//       },
-//     }
-//   } else if (type == 'carbonfet') {
-//     cc.thumbCluster = {
-//       oneofKind: 'carbonfetThumb',
-//       carbonfetThumb: {
-//         rowCurve: -225,
-//         columnCurve: -450,
-//         horizontalSpacing: 200,
-//         verticalSpacing: 205,
-//       },
-//     }
-//   }
-//   const cosc = toCosmosConfig(cuttleConf(cc), side)
-//   const coscthumb = cosc.clusters.find((c) => c.name == 'thumbs')!
-
-//   const thumb = c.clusters.find((c) => c.name == 'thumbs' && c.side == side)!
-//   thumb.clusters = coscthumb.clusters
-//   thumb.rotation = coscthumb.rotation
-//   thumb.position = coscthumb.position
-//   return c
-// }
-
-type Thumb = 'curved' | 'carbonfet' | 'manuform' | 'orbyl'
-const THUMB_CONFIG: Record<Thumb, { b64: string; n?: number[]; defaultN?: number }> = {
-  curved: {
-    b64:
-      'Ci8SExDAjwJAgICYAkjCmaCVkLwBUEMSFhDApwJAgIDMAkjCmaCVkLwBUIYBWDo4CAoWEhEQwANAgIAgSNCVgN2Q9QNQC1CeAgorEhEQwBtAgID4AUjmmfynkAtQVxIUEMAzQICApANI8JnEtdAwUHRYlQFQfwoYEhMQgD9AkrbtDEj6mejs8PwCUIYBUIICGAIiCgjIARDIARgAIABAy4v8n9AxSK2R3I3BkwY=',
-    n: [2, 3, 4, 5, 6],
-    defaultN: 5,
-  },
-  carbonfet: {
-    b64: 'ChASBhBAIA5AARIEIAVAATgTCiESEQiAMBDAgAJAAUiAgIz9A1ByEgoIgCAQQEABUIUBOAAKHBIPCIAwEEBAAUiAgIz9A1BaEgcIgCAgD0ABOBQYAiIKCMgBEMgBGAAgAEDXicymkDZIqY2AtvGXHA==',
-  },
-  manuform: {
-    b64:
-      'CoMBEhYIgDAQwMACIABAi4XYlhBIjYWAwN0NEhQIgDAQwAMgAECaxJYISI2FgMDdDRISEMAbIABArYXcA0iZiYSe4NwQEhMQwCcgAEDig9jQAUjpk5yXoPAREhIQwDMgAEDP4o84SIOPnJegvRISFBDAPyAAQPCFvJewAUjhncyNwNgSOAAYAiIKCMgBEMgBGAAgAECdjcys8DNIpqngxvCzCA==',
-    n: [2, 3, 4, 6],
-    defaultN: 6,
-  },
-  orbyl: {
-    b64: 'CgoSBRBAUPICOMAMCgsSBhDAgAIgKDioFAoJEgQQQCAoOJAcCgsSBhBAIChAADj4IwoYEhIQQCAAMMgBQICAgA1IgICwrAEwFjgAGAoiCgjIARDIARgAIABA25GknPA3SISPlNageA==',
-  },
-}
-
-export function setThumbCluster(c: CosmosKeyboard, type: Thumb, side: 'left' | 'right', howMany?: number) {
-  const { b64, n, defaultN } = THUMB_CONFIG[type]
+export function setPreset(c: CosmosKeyboard, name: 'center', type: CenterPreset, side: 'center', howMany?: number): CosmosKeyboard
+export function setPreset(c: CosmosKeyboard, name: 'thumbs', type: ThumbPreset, side: 'left' | 'right', howMany?: number): CosmosKeyboard
+export function setPreset(c: CosmosKeyboard, name: 'thumbs' | 'center', type: ThumbPreset | CenterPreset, side: 'left' | 'right' | 'center', howMany?: number) {
+  const { b64, n, defaultN } = name == 'thumbs' ? THUMB_CONFIG[type as ThumbPreset] : CENTER_CONFIG[type as CenterPreset]
   let cluster = decodeCosmosCluster(Cluster.fromBinary(Uint8Array.from(atob(b64), c => c.charCodeAt(0))))
   if (n) {
     const limit = howMany ?? defaultN ?? Infinity
@@ -200,35 +178,44 @@ export function setThumbCluster(c: CosmosKeyboard, type: Thumb, side: 'left' | '
   cluster.clusters.forEach(c => c.keys.forEach(k => k.profile.letter = undefined))
   if (side == 'left') cluster = mirrorCluster(cluster, c)
 
-  const thumb = c.clusters.find((c) => c.name == 'thumbs' && c.side == side)
-  if (!thumb) return c
-  if (thumb.type != cluster.type) thumb.curvature = cluster.curvature
-  thumb.type = cluster.type
-  thumb.clusters = cluster.clusters
-  thumb.rotation = cluster.rotation
-  thumb.position = cluster.position
+  const thumb = c.clusters.find((c) => c.name == name && c.side == side)
+  if (thumb) {
+    if (thumb.type != cluster.type) thumb.curvature = cluster.curvature
+    thumb.type = cluster.type
+    thumb.clusters = cluster.clusters
+    thumb.rotation = cluster.rotation
+    thumb.position = cluster.position
+  } else if (side == 'center') {
+    // Center clusters aren't included by default, so it needs to be added
+    c.clusters.push(cluster)
+    sortClusters(c.clusters)
+  }
   return c
 }
 
-const decodedClusters = mapObj(THUMB_CONFIG, ({ b64 }) => decodeCosmosCluster(Cluster.fromBinary(Uint8Array.from(atob(b64), c => c.charCodeAt(0)))))
-const mirroredDecodedClusters = mapObj(decodedClusters, c => mirrorCluster(c, undefined))
-
-export function getThumbN(c: CosmosKeyboard, side: 'left' | 'right') {
-  const thumb = c.clusters.find((c) => c.name == 'thumbs' && c.side == side)
+export function getPresetN(c: CosmosKeyboard, name: 'center', side: 'center'): { which: CenterPreset; options: number[]; n: number } | undefined
+export function getPresetN(c: CosmosKeyboard, name: 'thumbs', side: 'left' | 'right'): { which: ThumbPreset; options: number[]; n: number } | undefined
+export function getPresetN(c: CosmosKeyboard, name: 'thumbs' | 'center', side: 'left' | 'right' | 'center') {
+  const thumb = c.clusters.find((c) => c.name == name && c.side == side)
   if (!thumb) return
-  const whichThumb = objKeys(THUMB_CONFIG).find(k => THUMB_CONFIG[k].n && isThumb(c, k, side))
+  const whichThumb = Object.entries(name == 'thumbs' ? THUMB_CONFIG : CENTER_CONFIG) // @ts-ignore next line
+    .find(([k, v]) => v.n && isPreset(c, name, k, side))
+
   if (whichThumb) {
     return {
-      which: whichThumb,
-      options: THUMB_CONFIG[whichThumb].n!,
+      which: whichThumb[0] as CenterPreset | ThumbPreset,
+      options: whichThumb[1].n!,
       n: sum(thumb?.clusters.map(c => c.keys.length)),
     }
   }
 }
 
-export function isThumb(c: CosmosKeyboard, type: Thumb, side: 'left' | 'right') {
-  const cluster = (side == 'left' ? mirroredDecodedClusters : decodedClusters)[type]
-  const thumb = c.clusters.find((c) => c.name == 'thumbs' && c.side == side)
+export function isPreset(c: CosmosKeyboard, name: 'center', type: CenterPreset, side: 'center'): boolean
+export function isPreset(c: CosmosKeyboard, name: 'thumbs', type: ThumbPreset, side: 'left' | 'right'): boolean
+export function isPreset(c: CosmosKeyboard, name: 'thumbs' | 'center', type: ThumbPreset | CenterPreset, side: 'left' | 'right' | 'center') {
+  // @ts-ignore
+  const cluster: CosmosCluster = { left: mirroredDecodedClusters, right: decodedClusters, center: decodedCenterClusters }[side][type]
+  const thumb = c.clusters.find((c) => c.name == name && c.side == side)
   if (!thumb || thumb.clusters.length == 0) return false
 
   return thumb.clusters.every(c =>
@@ -256,7 +243,7 @@ export function testPrint(c: FullCuttleform) {
   }
   const cosmosBoard = toCosmosConfig(keyboard, 'right', false)
   cosmosBoard.clusters.forEach(c => c.clusters.length = 0)
-  setThumbCluster(cosmosBoard, 'curved', 'right', 1)
+  setPreset(cosmosBoard, 'thumbs', 'curved', 'right', 1)
   return fromCosmosConfig(cosmosBoard).right!
 }
 
@@ -287,6 +274,11 @@ export function getNKeys(kbd: CosmosKeyboard, type: PartType['type']) {
       : nRight
     nKeys += nRight + nLeft
   }
+  // Center cluster: counted once (no mirror).
+  const centerSide = kbd.clusters.find(c => c.side == 'center')
+  if (centerSide) {
+    nKeys += sum(centerSide.clusters.map(c => c.keys.filter(k => !type || (k.partType.type || c.partType.type || kbd.partType.type) == type).length))
+  }
   return nKeys
 }
 
@@ -344,6 +336,7 @@ function alphaColumns(kbd: CosmosKeyboard, cluster: CosmosCluster) {
 export function addRow(kbd: CosmosKeyboard, fn: (side: 'left' | 'right', alphas: number[], row: number, column: number) => string | null) {
   return mapClusters(kbd, cluster => {
     if (cluster.name !== 'fingers') return cluster // Only change fingers cluster
+    if (cluster.side === 'center') return cluster // No num/fn rows on center cluster
     const alphas = alphaColumns(kbd, cluster)
     return mapClusters(cluster, (col, i) => {
       const firstKey = col.keys.filter(a => !!a.row).sort((a, b) => a.row! - b.row!)[0]
@@ -351,7 +344,7 @@ export function addRow(kbd: CosmosKeyboard, fn: (side: 'left' | 'right', alphas:
       if (!PART_INFO[firstKey.partType.type || col.partType.type || kbd.partType.type!].keycap) return col // Skip if first key not a keycap
       const oldRow = firstKey?.profile.row
       const row = (firstKey?.row || 0) - 1
-      const letter = fn(cluster.side, alphas, i, cluster.clusters.length)
+      const letter = fn(cluster.side as 'left' | 'right', alphas, i, cluster.clusters.length)
       if (letter === null) return col // Skip adding key if fn returns null
       const key: CosmosKey = {
         profile: {
diff --git a/src/routes/beta/lib/firmware/qmk.ts b/src/routes/beta/lib/firmware/qmk.ts
index 25933e6f..97877155 100644
--- a/src/routes/beta/lib/firmware/qmk.ts
+++ b/src/routes/beta/lib/firmware/qmk.ts
@@ -196,7 +196,7 @@ function generateMCUConfH(options: QMKOptions) {
 function generateRulesMK(config: FullGeometry) {
   const driver = Object.values(config).flatMap(c => pointingDevices(c))[0]
   const driverSide = objKeys(config).filter(c => pointingDevices(config[c]!).length)[0]
-  const driverSuffix = { right: '_RIGHT', left: '', unibody: '' }[driverSide] || ''
+  const driverSuffix = { right: '_RIGHT', left: '', unibody: '', center: '' }[driverSide] || ''
 
   const display = Object.values(config).flatMap(c => displays(c))[0]
 
diff --git a/src/routes/beta/lib/modelGLTF.ts b/src/routes/beta/lib/modelGLTF.ts
index 3f1a4779..7c44e030 100644
--- a/src/routes/beta/lib/modelGLTF.ts
+++ b/src/routes/beta/lib/modelGLTF.ts
@@ -8,12 +8,12 @@ import { boardGeometries } from '$lib/loaders/boardElement'
 import { fromGeometry } from '$lib/loaders/geometry'
 import { keyGeometries } from '$lib/loaders/keycaps'
 import { partGeometries } from '$lib/loaders/parts'
-import type { Center, Geometry } from '$lib/worker/config'
+import type { Center, Geometry, KeyboardSide } from '$lib/worker/config'
 import * as THREE from 'three'
 import type { FullGeometry, KeyboardMeshes } from './viewers/viewer3dHelpers'
 import type { WorkerPool } from './workerPool'
 
-export async function modelAsScene(pool: WorkerPool<typeof import('$lib/worker/api')>, geometry: FullGeometry, side: 'left' | 'right' | 'unibody') {
+export async function modelAsScene(pool: WorkerPool<typeof import('$lib/worker/api')>, geometry: FullGeometry, side: KeyboardSide) {
   const geo = geometry[side]!
   const conf = geo.c
   const wall = pool.execute((p) => p.cutWall(conf))
@@ -128,7 +128,7 @@ export function cosmosMaterial(kind: 'key' | 'case', opts: { opacity?: number; b
   })
 }
 
-export async function renderedModelAsGroup(geometry: FullGeometry, side: 'left' | 'right' | 'unibody', meshes: KeyboardMeshes, cosmosMaterials = false) {
+export async function renderedModelAsGroup(geometry: FullGeometry, side: KeyboardSide, meshes: KeyboardMeshes, cosmosMaterials = false) {
   const geo = geometry[side]!
   const conf = geo.c
 
@@ -231,7 +231,7 @@ export async function renderedModelAsGroup(geometry: FullGeometry, side: 'left'
   return group
 }
 
-export async function renderedModelsAsScene(geometry: FullGeometry, meshes: ['left' | 'right' | 'unibody', KeyboardMeshes][], center: Center, cosmosMaterials = false) {
+export async function renderedModelsAsScene(geometry: FullGeometry, meshes: [KeyboardSide, KeyboardMeshes][], center: Center, cosmosMaterials = false) {
   const scene = new THREE.Scene()
   for (const [side, model] of meshes) {
     const cent = center[side]!
diff --git a/src/routes/beta/lib/viewers/Viewer3D.svelte b/src/routes/beta/lib/viewers/Viewer3D.svelte
index 3a5bc943..bd28a5df 100644
--- a/src/routes/beta/lib/viewers/Viewer3D.svelte
+++ b/src/routes/beta/lib/viewers/Viewer3D.svelte
@@ -9,6 +9,7 @@
     encodeTuple,
     tupleToXYZ,
     type Center,
+    type KeyboardSide,
   } from '$lib/worker/config'
   import Trsf from '$lib/worker/modeling/transformation'
   import {
@@ -359,10 +360,7 @@
     if (event.keyCode == 17) snapRotation = false
   }
 
-  function getClickedSide(
-    config: CosmosKeyboard,
-    n: number | null
-  ): 'unibody' | 'right' | 'left' | null {
+  function getClickedSide(config: CosmosKeyboard, n: number | null): KeyboardSide | null {
     if (config?.unibody) return 'unibody'
     if (n == null) return null
     return nthKey(config, n).cluster.side
diff --git a/src/routes/beta/lib/viewers/ViewerDev.svelte b/src/routes/beta/lib/viewers/ViewerDev.svelte
index 5cfc71f5..74404402 100644
--- a/src/routes/beta/lib/viewers/ViewerDev.svelte
+++ b/src/routes/beta/lib/viewers/ViewerDev.svelte
@@ -49,6 +49,12 @@
         $protoConfig.clusters.find((c) => c.side == 'right' && c.name == 'thumbs')
       ).substring(0, 290)}&hellip;
     </div>
+    {#if $protoConfig.clusters.some((c) => c.side == 'center' && c.clusters.length)}
+      <div class="mt-5">Encoded Center Cluster</div>
+      <div class="code">
+        {clusterToB64($protoConfig.clusters.find((c) => c.side == 'center'))}
+      </div>
+    {/if}
   {/if}
   {#if geometry}
     <div class="mt-5">Key and Connector Positions</div>
diff --git a/src/routes/beta/lib/viewers/viewer3dHelpers.ts b/src/routes/beta/lib/viewers/viewer3dHelpers.ts
index 19a6399f..70d9ac90 100644
--- a/src/routes/beta/lib/viewers/viewer3dHelpers.ts
+++ b/src/routes/beta/lib/viewers/viewer3dHelpers.ts
@@ -1,6 +1,6 @@
 import { UNIFORM } from '$lib/geometry/keycaps'
 import { adjacentKeycapLetter } from '$lib/geometry/layouts'
-import { decodeTuple, type Geometry } from '$lib/worker/config'
+import { decodeTuple, type Geometry, type KeyboardSide } from '$lib/worker/config'
 import { type CosmosCluster, type CosmosKey, type CosmosKeyboard, cosmosKeyPosition, nthKey } from '$lib/worker/config.cosmos'
 import type { ShapeMesh } from '$lib/worker/modeling'
 import Trsf, { Vector } from '$lib/worker/modeling/transformation'
@@ -23,7 +23,7 @@ export type KeyboardMeshes = {
   supportGeometries?: ShapeMesh[]
 }
 
-type Full<T> = { left?: T; right?: T; unibody?: T }
+type Full<T> = { left?: T; right?: T; center?: T; unibody?: T }
 
 export type FullKeyboardMeshes = Full<KeyboardMeshes>
 export type FullGeometry = Full<Geometry>
@@ -238,7 +238,7 @@ export function formatHoming(key: CosmosKey) {
   return key.profile.home[0].toUpperCase() + key.profile.home.substring(1)
 }
 
-export function kbdOffset(kbd: 'left' | 'right' | 'unibody') {
+export function kbdOffset(kbd: KeyboardSide) {
   return 0
   // if (kbd == 'left') return -90
   // if (kbd == 'right') return 90
diff --git a/src/routes/beta/lib/viewers/viewerHelpers.ts b/src/routes/beta/lib/viewers/viewerHelpers.ts
index 93647ebd..72431d22 100644
--- a/src/routes/beta/lib/viewers/viewerHelpers.ts
+++ b/src/routes/beta/lib/viewers/viewerHelpers.ts
@@ -146,7 +146,7 @@ export function makeBox(cx: number, cy: number, cz: number, w: number, h: number
   return new THREE.BoxGeometry(w, h, d).translate(cx, cy, cz)
 }
 
-type Full<T> = { left?: T; right?: T; unibody?: T }
+type Full<T> = { left?: T; right?: T; unibody?: T; center?: T }
 
 const SEPARATION = 20
 export function fullSizes(geo: Full<THREE.BufferGeometry[]>) {
@@ -158,10 +158,12 @@ export function fullSizes(geo: Full<THREE.BufferGeometry[]>) {
       geo.left!.map((x) => ({ mesh: x, matrix: new THREE.Matrix4().makeScale(-1, 1, 1) })),
     )
     const rightBox = boundingBox(geo.right!.map((g) => g))
+    const centerBox = geo.center ? boundingBox(geo.center.map((g) => g)) : null
     const leftSize = leftBox.getSize(new THREE.Vector3())
     const rightSize = rightBox.getSize(new THREE.Vector3())
     const bothSize = leftBox.union(rightBox).getSize(new THREE.Vector3())
     bothSize.x += SEPARATION - (rightBox.min.x - leftBox.max.x)
+    if (centerBox) bothSize.x += SEPARATION + centerBox.max.x - centerBox.min.x
     return { left: leftSize, both: bothSize, right: rightSize }
   }
 }