Columns is a match-three arcade puzzle game developed by Jay Geertsen in 1989. It had been ported to various systems before being released commercially by Sega in arcades and home consoles. Similar in structure to Tetris and Dr. Mario, the player is given a column of three vertically stacked gems of different colours–red, orange, yellow, green, blue, and purple. The player may move the falling gems left and right to control where the gems drop. Unlike Tetris, the player cannot control the orientation of the gems, that is the set of three gems always remains vertical. Instead, the player can manipulate the order of the colours of the three gems. When three gems of the same colour line up vertically, horizontally, or diagonally, the gems disappear and the player scores points. Any unsupported gems fall downwards, potentially forming new matches for a chain reaction.