Let There Be Light

You've got three basic colors : RED, BLUE and YELLOW. You can mix two of them: RED+BLUE=PURPLE RED+YELLOW=ORANGE BLUE+YELLOW=GREEN Then you need to have the three basic colors on one single block in order to create a white block: PURPLE + YELLOW = WHITE RED + GREEN = WHITE BLUE + ORANGE = WHITE Once 3 white blocks are aligned, they disappear.