The players alternate placing their six discs onto the 3x3 playing area. The object is to form a stack of three of your own colour. During play, no stack may grow taller than three in height. Once all placements are done, on your turn you move a piece from atop its stack to any other stack --covered pieces cannot move. You pass if all your pieces are covered. When two players play, each uses two colors. (There is no three-player game)