The Play: turns rotate clockwise around the board starting with Blue. On each turn, the player must do two things play the top tile from the stack of spares move one of his runners in a path that passes over the tile you just played, and ends at an empty stop or home circle. If you cannot do both, then you must pass. You can never just place a tile, or move a runner without placing a tile, or move a runner that does not use one of the paths on the new tile. If you were playing with a real board and real tiles, determining that no moves are possible, and exactly which tile placements are legal, can be difficult. One of the advantages of the computer is that it knows, and will show you what's legal, and won't let you make an illegal move. Yah!