Now I've gone too far

Optical illusions.

(A) There is a cool sculpture of a house, which looks like something that a kid would draw, in the NGA sculpture garden that is amazing to walk by. They inverted the concavity of the house, so that the roof corner which should be closest to you is the furthest away. When you walk by it, the geometry does a really odd shift manuever, which as you might already gather, is a lot better seen than described. (it's kinda like this)

(B) I've wondered about subliminally including optical illusions into scientific figures just as a little Easter Egg. I guess the page above would be a place to start looking for ideas.