The Functions are avatars of Puzzlebox's systems.
They're also the people who run the muck, more commonly known as "wizards". [OOC note: Except for YET. YET is just a hypothetical Function there purely for use by players who would like to spoof a Function action during the course of a scene. As a rule of thumb, YET is the Function in charge of experimentation, inexplicable whimsy, and avant-garde causality; thus, it would prefer not to be included in canonical plot. :) ]