GridMaster4 is a game simulation of a four-player version of the Android single player game, The Grid Master (available on Google play).
GridMaster4 is played on 20x20 grid board, which allows for 400 cells. Each player starts with 100 tiles of the same color, depending on their position in the initial player order: 1=orange, 2=magenta, 3=lime green, and 4=aqua. A tile is the same size as a cell. Each player’s tiles are numbered, 1 through 100. All tiles are initially full-color to indicate an “active” state, but can be muted with a darker version of the color to indicate an “inactive” state. Player scores are recorded in an area off the board, and initially set to zero.
For each player’s initial turn, the “1” tile is placed, color-side up, in any open/unoccupied cell. With this move, the player’s score becomes “1.”
For each subsequent turn of normal game play, players select from up to 32 legal move options. A legal move is defined as any open cell that is exactly 3 cells up, down, left, or to the right of an active tile, or exactly 2 diagonal cells (any of the four). If an active tile is within three cells of a board edge, there will be fewer legal moves available to build on that tile. It is also possible that a cell would be a legal move from more than one active tile, which would also reduce the total number of legal move options available to a player.
Once a move option is selected, the player places their next tile (“2”, then “3”, and so on) in that cell, and the tile number becomes the player’s score. Any active tile that is within a legal move from the newly placed tile (which would at least include the tile which the player just built on) is then made inactive, appearing muted.
When a player has no move possibilities, they are “blocked” and removed from any further play. The next turn allows each player to place a tile in any open cell, and then normal game play resumes.
A player wins the game by placing their “100” tile on the board, or having the largest numbered tile on the board when all players are blocked.