Dutch artist M.C. Escher's most famous drawing is titled *Relativity* and shows a fantastic world, where people climb on stairs in all directions. Depending on your point of reference, up becomes down, wall becomes floor, and floor becomes ceiling. This model translates Escher's 1953 drawing into three dimensional computer space.
![](https://upload.wikimedia.org/wikipedia/en/a/a3/Escher%27s_Relativity.jpg)