The game is played on a square board divided into 20 rows and 20 columns, for a total of 400 squares. There are a total of 84 game tiles, organized into 21 shapes in each of four colors: blue, yellow, red and green. The 21 shapes are based on��free polyominoes��of from one to five squares (one monomino, one��domino, two��trominoes/triominoes, five��tetrominoes, and 12��pentominoes).
The standard rules of play for all variations of the game are as follows:
- Order of play is either clockwise or counter-clockwise.
- The first piece played of each color is placed in one of the board's four corners. Each new piece played must be placed so that it touches at least one piece of the same color, with only corner-to-corner contact allowed���edges cannot touch. However, edge-to-edge contact is allowed when two pieces of different color are involved.
- When a player cannot place a piece, he or she passes, and play continues as normal. The game ends when no one can place a piece.
When a game ends, the score is based on the number of squares in each player's pieces on the board (e.g. a tetromino is worth 4 points). If a player played all of his or her pieces, he or she gets a bonus score of +20 points if the last piece played was a monomino, +15 points otherwise.