A ball is moving inside the square.Each side of the square has a specific color. The ball is likewise colored with one of these colors. All you have to do is to ensure that the ball won't strike the side with the exact same color and you can do this by touching the screen and altering the ball's color. After each time that you change the ball's color, it will also change the direction that it moves. You will lose if you fail to alter the ball's color properly or if you alter it when it's not necessary.