I'm a big fan of M.C. Escher's Artworks and constantly wondering how he achieved this genius art. I based the illustration on the mathematical formula of Tessellations, but tried to give it a personal note in the end. Anybody interested in this topic should pay a visit to tessellations.org
Laters, I gave it a try with another animal shape - 2 horses which should fit neatless in a circle. Originally inspired by Escher and the yin yang symbol, so I could play with negative/positive space.