The player is presented with a grid (by default, 3x3) and nine square tiles, each with a number on each edge. The objective of the game is to place the tiles in the grid in the proper position as fast as possible. Two tiles can only be placed next to each other if the numbers on adjacent faces match.
- On a board there are horizontal and vertical pairs that must match and numbers along the edges that can be chosen arbitrarily. Hence there are choices of 10 digits, i.e. possible boards.