Added to the conventional FPS control keys are two extra keys that move the player in ana and kata direction in 4d space. If you go in this extra direction the space around you changes, the room transforms.

Why la; I knew't, this Propheticall tongue of mine never faild me; my mother was halfe a witch, never any thing that ſhe foreſpake, but came to paſſe: […]

Archbishop Whately used to say ‘Throw dirt enough, and some will stick;' well, will stick, but not, will stain. I think he used to mean ‘stain,' and I do not agree with him.

an inveterate idler