update/add new example programs

Author: lee2sman

docs/assets/examples/basic-pong.gif

@@ -42,6 +42,7 @@ end
 
 ## Related Examples
 
+* [Doodle Draw](doodle-draw.md)
 * [Animation with Events](animation-and-variables-animation-with-events.md)
 * [Conditions](animation-and-variables-conditions.md)
 

docs/assets/examples/drawing-software.gif

@@ -0,0 +1,149 @@
+# Basic Pong
+
+This is a basic implementation of Pong in L5. 
+
+It demonstrates:
+
+* [table](/reference/table)-based game objects
+* mouse input
+* simple AI
+* collision detection
+* score tracking
+* game loop structure
+* use of randomness
+
+From here, you can add additional features such as:
+
+* speeding up the ball on each paddle hit until a player scores 10 points to win
+* a win/lose screen that appears when a player gets 10 points, showing who won and final scores. Click to reset the game and start again.
+* smarter enemy AI that better anticipates the direction of the ball's movement
+* more players - try adding player 3 and 4 along the top and bottom. Each player should have 2 keys for moving their player paddle.
+
+For more ideas, check out Pippin Barr's [PONGS](https://pippinbarr.com/pongs/info/).
+
+![animation of a game of pong with 2 player paddles trying to hit the red ball](/assets/examples/basic-pong.gif "A basic game of pong with 2 player paddles trying to hit a red ball")
+
+```lua
+require("L5")
+
+function setup()
+  size(800,600)
+  windowTitle("Pong")
+  rectMode(CENTER)
+  
+  -- Global variables
+  p1 = { -- Player 1 (left, controlled by mouse)
+    x = 15,
+    y = height/2,
+    w = 30,
+    h = 120,
+    score = 0
+  }
+  
+  p2 = { -- Player 2 (right, AI controlled)
+    x = width-15,
+    y = height/2,
+    w = 30,
+    h = 120,
+    score = 0,
+    yspeed = 5
+  }
+  
+  b = { -- The ball
+    x = width/2,
+    y = height/2,
+    w = 30,
+    h = 30,
+    xspeed = random(3,10),
+    yspeed = random(3,10)
+  }
+  
+  noCursor()
+end
+
+function draw()
+  background(180,0,180)
+  
+  -- Left player (P1)
+  fill(0,255,0)
+  rect(p1.x, p1.y, p1.w, p1.h)
+  
+  -- Right player (P2)
+  fill(0,0,255)
+  rect(p2.x, p2.y, p2.w, p2.h)
+  
+  -- Ball
+  fill(200,0,0)
+  ellipse(b.x, b.y, b.w, b.h)
+  
+  -- Scores
+  fill(0)
+  textSize(24)
+  text(p1.score, width/4, 20)
+  text(p2.score, 3/4*width, 20)
+  
+  -- Player movement
+  p1.y = mouseY
+  
+  -- AI movement (simple - just follows ball)
+  if b.y < p2.y then
+    p2.y = p2.y - p2.yspeed
+  else
+    p2.y = p2.y + p2.yspeed
+  end
+  
+  -- Ball movement
+  b.x = b.x + b.xspeed
+  b.y = b.y + b.yspeed
+  
+  -- Wall collision (top/bottom)
+  if b.y > height or b.y < 0 then 
+    b.yspeed = b.yspeed * -1 
+  end
+  
+  -- Scoring (checking for wall collisions)
+  if b.x < 0 then 
+    p2.score = p2.score + 1
+    resetBall()
+  end
+  
+  if b.x > width then 
+    p1.score = p1.score + 1
+    resetBall()
+  end
+  
+  -- Paddle collision
+  -- Player 1 (left)
+  if b.x < p1.x + p1.w/2 and 
+     b.y < p1.y + p1.h/2 and 
+     b.y > p1.y - p1.h/2 then
+    b.x = b.x + 10
+    b.xspeed = b.xspeed * -1
+  end
+  
+  -- Player 2 (right)
+  if b.x > p2.x - p2.w/2 and 
+     b.y > p2.y - p2.h/2 and 
+     b.y < p2.y + p2.h/2 then
+    b.x = b.x - 10
+    b.xspeed = b.xspeed * -1
+  end
+end
+
+function resetBall()
+  b.x = width/2
+  b.y = height/2
+  -- Random direction
+  b.xspeed = random(3,10) * (random() > 0.5 and 1 or -1)
+  b.yspeed = random(3,10) * (random() > 0.5 and 1 or -1)
+end
+```
+
+## Related References
+
+* [table](/table.md) - changing color modes
+
+## Related Examples
+
+* [Drawing software](/examples/drawing-software)
+

docs/assets/examples/image-transparency.gif

@@ -0,0 +1,59 @@
+# Drawing Software
+
+This is a basic implementation of a program to draw doodles, using random colors.
+
+It demonstrates:
+
+* working with colors
+* random RGB color selection
+* input and event handling
+* current and previous frame mouse positioning
+
+From here, you can add additional features such as:
+
+* buttons to select different colors and brush sizes
+* draw with stamps or photos
+* the ability to save one's drawing to the computer
+* a reset button to clear the screen
+* randomly selected prompts that suggest what to draw
+* a symmetrical drawing mode
+* more experimental features!
+
+For more ideas, check out [Meeting Mr. Kid Pix](https://youtu.be/BxoY-_HQOK0?si=8LWjmoNAkNWWydSk).
+
+![Various doodle lines of different colors are drawin in the window](/assets/examples/drawing-software.gif "Various doodle lines in different colors are drawn in the window")
+
+```lua
+require("L5")
+
+function setup()
+  size(800,600)
+  windowTitle("Drawing software")
+
+  background("midnightblue")
+  strokeWeight(5)
+end
+
+function mouseDragged()
+  line(mouseX, mouseY, pmouseX, pmouseY)
+end
+
+function mousePressed()
+  stroke(random(255),random(255),random(255))
+end
+
+```
+
+## Related References
+
+* [mouseDragged()](/reference/mouseDragged) 
+* [mousePressed()](/reference/mousePressed)
+* [mouseX](/reference/mouseX)
+* [mouseY](/reference/mouseY)
+* [pmouseX](/reference/pmouseX)
+* [pmouseY](/reference/pmouseY)
+
+## Related Examples
+
+* [Basic Pong](/examples/basic-pong)
+

docs/assets/examples/random-robot-objects.gif

@@ -7,13 +7,19 @@
 
 ## Animations and Variables
 
-* [Drawing Lines](animation-and-variables-drawing-lines.md) - Draw with the mouse.
+* [Doodle Draw](doodle-draw.md) - A basic drawing program tracking mouse movements
+* [Drawing Lines](animation-and-variables-drawing-lines.md) - A drawing program demonstrating HSB colorMode
 * [Animation with Events](animation-and-variables-animation-with-events.md) - Pause and resume animation.
-* [Conditions](animation-and-variables-conditions.md) - Use if and else statements to omake decisions while your sketch runs.
+* [Conditions](animation-and-variables-conditions.md) - Use if and else statements to make decisions while your sketch runs.
+* [Basic Pong](basic-pong.md) - A simple program demonstrating a basic implementation of pong with enemy AI player
 
 ## Imported Media
 
 * [Words](imported-media-words.md) - Load fonts and draw text.
 * [Copy Image Data](imported-media-copy-image-data.md) - Paint from an image file onto the canvas.
 * [Image Transparency](imported-media-image-transparency.md) - Make an image translucent on the canvas.
 * [Video Player](imported-media-video.md) - Create a player for video playback and stylize in the window
+
+## Object-Orientation Patterns
+
+* [Random Robot Objects](random-robot-objects.md) - Demonstrates two different Lua patterns - classes with metatables and simple table objects

docs/examples/animation-and-variables-drawing-lines.md

@@ -0,0 +1,145 @@
+# Random Robot Objects
+
+This object-oriented programming example program demonstrates two different Lua patterns - classes with metatables (Robot) and simple tables with methods (box). It consists of a Robot class definition and simple box object. 
+
+The box object demonstrates a simpler object-oriented structure of a table with methods. Lua's power of [first-class functions](https://softwarepatternslexicon.com/lua/lua-programming-fundamentals/first-class-functions-and-closures/) is represented here.
+
+A first-class function means they can be:
+
+* Stored in tables (like in the `box` table)
+* Assigned to variables (like `display = function(self) ... end`)
+* Passed as arguments to other functions
+* Returned from functions
+
+The `box` object demonstrates this with `display` and `move` functions stored as values in the box, just like `x`, `y` and `size` are numbers.
+
+The Robot demonstrates uses of [metatables](https://www.tutorialspoint.com/lua/lua_metatables.htm).
+
+* `Robot.__index = Robot` sets up the metatable
+* `setmetatable(robot, Robot)` links each instance to the Robot table
+* This enables [method lookup](https://cyevgeniy.github.io/luadocs/02_basic_concepts/ch04.html) - when you call `robot:move()`, Lua looks in the Robot table to find the `move` function
+
+Advanced ways to extend the program:
+
+* add more robot behaviors - make robots change colors when they collide with each other
+* score counter - count how many times the box teleports to robots
+* different robot types - a FastRobot that moves twice as fast as the others
+* mouse interaction - Create new robots at the mouse position when clicked
+* Box trail - a line showing the box's history
+* Chase - make robots chase the box
+* power-ups - add collectible items that change robot speed, size or behavior
+* animated sprites - multiple images to animate movement
+
+![Random robots moving around the screen. One robot grabs the yellow box, but it is stolen again several times by other robots](/assets/examples/random-robot-objects.gif "Random robot objects roam around the screen. One robot grabs the yellow box, but it is again stolen several times by other robots.")
+
+```lua
+require("L5")
+
+-- Note: The Robot class definition below could be moved to a separate file robot.lua
+-- and then loaded with: local Robot = require("robot")
+
+Robot = {}
+Robot.__index = Robot -- Tells Lua to use Robot's metatable to find methods
+
+-- Global vars
+robots = {}  -- Table to hold all robot instances
+robotImg = nil
+
+function setup()
+  size(800, 600)
+  windowTitle("Robots OOP example")
+  robotImg = loadImage("assets/robot.png")
+  imageMode(CENTER)
+  rectMode(CENTER)
+  strokeWeight(3)
+  fill("gold")
+  stroke("goldenrod")
+  
+  -- Initialize box position
+  box.x = random(width)
+  box.y = random(height)
+  
+  -- Create 10 robots
+  for i = 1, 10 do
+    table.insert(robots, Robot:new())
+  end
+end
+
+function draw()
+  background("lightblue")
+  
+  -- Update and draw box
+  box:move()
+  box:display()
+  
+  -- Update and draw all robots
+  for i = 1, #robots do
+    robots[i]:move()
+    robots[i]:display()
+  end
+end
+
+-- Robot class definition
+function Robot:new(x, y, w, h)
+  local robot = {
+    x = x or random(width), 
+    y = y or random(height), 
+    w = w or 70, 
+    h = h or 70,
+    xspeed = random(-2, 2), 
+    yspeed = random(-2, 2)
+  }
+  setmetatable(robot, Robot)  -- Links the instance to Robot class
+  return robot
+end
+
+function Robot:move()
+  self.x = self.x + self.xspeed 
+  self.y = self.y + self.yspeed
+  
+  -- Bounce off walls
+  if self.y > height or self.y < 0 then 
+    self.yspeed = self.yspeed * -1 
+  end
+  if self.x > width or self.x < 0 then 
+    self.xspeed = self.xspeed * -1 
+  end
+end
+
+function Robot:display()
+  image(robotImg, self.x, self.y, self.w, self.h)
+end
+
+-- Box object using simple table with methods
+-- Demonstrates first-class functions stored as table values
+box = {
+  x = nil,  -- Initialized in setup() after random() is seeded
+  y = nil,
+  size = 40,
+  
+  display = function(self)
+    square(self.x, self.y, self.size)
+  end,
+  
+  move = function(self)
+    -- Teleport to nearest robot if close enough
+    for i = 1, #robots do
+      if dist(self.x, self.y, robots[i].x, robots[i].y) < self.size then
+        self.x = robots[i].x    
+        self.y = robots[i].y
+        break
+      end
+    end
+  end
+}
+```
+
+## Related References
+
+* [for](/reference/for)
+* [imageMode()](/reference/imageMode)
+* [loadImage()](/reference/loadImage)
+* [rectMode()](/reference/rectMode)
+* [table](/reference/table) 
+* [random()](/reference/random)
+