White blocks (or black blocks) are a special kind of block that only exists in non-Mono characters. They do not match with any other color, each other, or wild card blocks. Instead, they go out of the grid when they reach the bottom, giving you a fixed amount of points each, normally 2000, irrespective of any bonuses, although the Multiply Powerup can multiply the score. The only difference between the two is that White blocks appear when you are using the black or grey backgrounds, and Black blocks with the white background.