Coloris is a computer game that was originally released in 1990 for Commodore Amiga. It was later ported to Atari ST. The game play is similar to Tetris and Columns. Like in Tetris, blocks fall from top of the screen to a well. The blocks consist of three squares of different colours. The blocks cannot be rotated, but the order of the colours can be switched. If three or more squares of same colour are adjacent, they disappear, blocks above them fall down, and may trigger a chain reaction.