OK, I lied. I have one more cool thing to post. Notes on the Denial of Perspective is a page that demonstrates paintings of seemingly random lines and colors that, when viewed from a certain point in space, form an image. The paintings are by Felice Varini. I would imagine that seeing some of these paintings in real life could totally throw your mind. It’s pretty cool 
I want that in my office.
See also: http://www.saturn9.ws/gallery/v/andy/sidewalk/
Reminds me of that.