M.C. Escher was a mathematically inspired artist who created lithographs, woodcuts and sketches of impossible-looking buildings. His images challenge the mind as he plays with the idea of reality and relative space.
In August, 2010, a computer scientist named Gershon Elber created software that allowed him and his team to design real objects that look like an illusion when seen at the right angle. He then used a 3D printer to create a real life version of Escher's Belvedere. It took 27 hours to print and is absolutely fascinating to see.