Are you prepared to have your mind blown? Ready? Okay, check out the Escherian Stairwell [1]. And while you are puzzling over that, remember the words of Sherlock Holmes [2]: “that when you have eliminated the impossible, whatever remains, however improbable, must be the truth [3]” (links via GoogleMyFacePlusSpaceBook).
[1] https://www.youtube.com/watch?v=iBY4HaAngaA
[2] http://en.wikipedia.org/wiki/House_(TV_series)#References_to_Sherlock_Holmes