This game involves filling 4x4 square grids with balls of a single colour, by dropping columns of balls onto them. You can move and rotate the grids, but dropping balls into squares which are already full is not allowed. In the first level only black balls are used, but at higher levels more colours appear, sometimes with more than one colour in the same column. The palette and blot also appear later on. Drop the palette onto a ball to change it to the predominant colour in that grid, or drop the blot onto a ball to remove it.