From Alphapedia Complexia
Alpha Complex consists of endless corridors, huge open plazas, towering blocks and just about every other urban configuration you can possibly imagine. Importantly, every part of a Alpha Complex is coloured according to security clearance. Much of the lower levels are used by the lower level clearances, such as the INFRAREDs who work in the huge food vats. The top levels are usually reserved for the ULTRAVIOLET High Programmers. The rest of the citizens mainly live and work somewhere in the middle.