"Here optical illusions are integrated in interior designs. It is really quite a nice idea to do this. The visitors who aren't standing in the proper angle won't have a clue about the concept. They wont be able to get why these lines & curves are painted on the walls. This way you can choose whom to share this little secret with."
Link

Now that is wicked! But I can't help but to think that it would screw with people too much...

WICKED! First it looks like real but then there's always some missing parts