An egg that is pushed so god damn hard that it is forced into an square like shape.
You can also make a square egg by acting like its dad and beating the shit out of it.
An individual who has allowed ones occupational environment define ones personality, to the point of behaving as if one is always within the four walls of an office.
That's just how squares are! They take everything serious, can't relax, and don't know how to have fun.