You Always Remember Your First

...MC Escher carving. What did you think I meant?
It seems a long time ago now, but shortly after I started boxing, I discovered Postal letterboxes. Since my girls were still pretty little, getting out was tricky. Postals hit the spot for me. "Theosophy" was one of my first and part of Celtic Quinn's MC Escher ring. I was completely intimidated. I attempted to carve "Blowball" first, but threw the design and stamp in the garbage after hours of frustration (that's another story). Theosophy was my fallback. And I love him. He has gone around several times since, but has since been retired. I don't know if I could bear to lose him.
What is your favorite Escher design? And have you carved it yet?