Quartet is a 1986 arcade game by Sega. Quartet allows one to four players to guide a set of characters through a base taken over by an army of robots. Players control either Joe (yellow), Mary (red), Lee (blue) or Edgar (green) across a number of sideways-scrolling levels. The object of the game is to advance through the level, fighting opponents that come out of portals in the walls, and eventually defeat a boss that carries the door key used to open the “exit door” for the level.