A simple mind game which needs extreme concentration and intelligence. There are 16 gray balls in the main game space, and you, in your turn, change the color of up to 3 of them to blue at one time by clicking on them or dragging them horizontally or vertically. When no gray ball remains any more, the game is over, and the last player of the game becomes the loser of the game. So to win the game, you have to make the opposite player (maybe your computer or aperson on the Internet) change the color of the last gray ball (or balls).