See also http://escherdroste.math.leidenuniv.nl/ http://escherdroste.math.leidenuniv.nl/ for (what I find) a more interesting kind of Escherization. (The UWate

See also http://escherdroste.math.leidenuniv.nl/ http://escherdroste.math.leidenuniv.nl/ for (what I find) a more interesting kind of Escherization. (The UWaterloo one is about taking an arbitrary shape and tweaking it to make a plane tessellation, and some generalizations of that. The Leiden one is about the sort of nonlinear self-containment found in (e.g.) Escher's "Print Gallery".) [EDITED to fix an error -- gjm]