An image of the green Crossover.

Crossover is a Nintendo puzzle game released in 1983 that cost ¥1000. Today it is one of the rarest Gunpei Yokoi-designed toys ever manufactured. It's a 4x4 square object with a window that shows a grid of 16 squares. Sliders are present that allow the player to slide the tiles back and fourth one by one. On the outskirts of the 16 colored tiles are white concave sections in which the tiles can be placed in order to move the board around.