#2 (HB) pencil on 11"x17" (A3) paper. Colorized in Photoshop 7.
This tessellation won first place at WorldOfEscher.com/contest/ last year... my second of three consecutive wins.
People may recognize a thematic similarity to Escher's "reptiles" piece, but please be aware that the two tessellation patterns in my piece are entirely original-- that Escher piece, aside from having a book and some tessellated reptiles, is otherwise completely different.
This sketch was one of my all-time favorite pieces of work. The perspective is slightly wonky, but otherwise I'm very happy with it.