In turn, a player drops a marble in any one of the three holes at the top of the device. The device contains eight flip-flops; three on the top row, two on the middle row and three on the bottom row. A flip-flop will change a window’s color from one to the other every time a marble hits it. The marble will exit the device from the left or the right. A player may continue taking a turn as long as the marble exits the device from the side chosen by that player. The object of this puzzle-game is to get a pre-determined sequence of colors to be revealed in the eight windows.