Yoshi's Egg, known as Yoshi in America and Mario & Yoshi in Europe and Australia, is a video game released for the Nintendo Entertainment System and Game Boy. There are four columns. Objects fall from the top of the screen in random columns, if they pile up to the top, you lose. Some of the objects are top and bottom halves of Yoshi eggshells. Sandwich other objects between two appropriate egg halves to score high. You can switch any two adjacent columns. Any object that has touched the ground will move with a column, while objects which are still falling will not.