This is a copy in 3D of the M.C.Escher picture "Relativity". Escher was a brilliant draughtsman as well as everything else, making a 3D model possible from his drawings (at least in this case).
Building the model was not straight forward however. Working out what went behind what in such a scene is a real brain twister! And his lighting I couldn't reproduce, I would get shadows from other bits where Escher could ignored them.
I couldn't resist adding the Daleks, what with their problems with stairs.