To take the topic of illusions further, take a look at this amazing castle that was cut out of a single sheet of paper by artist Nadezhda Bokovikova. All it is - a cut and folded piece of paper, yet you get an illusion of a huge mass of stone floating in front of you in a crazy gothic tangle of staircases and arches.
Nadezhda photographed the process of creating the castle and shared the pictures on her blog. She also wrote about her teacher and told the story behind the idea of the castle in another article.