First off, I did Mroogle this topic and it returned an archived thread from Nov. 2002. That said, I've spent probably the last ten or fifteen minutes looking at these five LEGO Escher models. They're the last five links on the page. That's some pretty crazy planning/ sculpting/ dedication. That guy has some other really neat LEGO sculpture listed on his website. If anyone's interested, I found it when I was reading the 'Inception' Wikipedia page where I clicked into the Penrose Staircase where I found the link in the references section.