Mike, your images are very nice. Print Gallery is my favorite of all Escher drawings, and the only one I have a print of (since 1973, even). I've been known to call it a "reality manifold" since locally (though not globally) it's realistic, just as a manifold can be locally but not globally Euclidean. (Or like integrating f(z) = 1/z on C, which is possible in an open set not surrounding the origin, but not in one that does.) But I've never believed that it's related to complex variables in the way claimed in < http://www.ams.org/notices/200304/fea-escher.pdf >. --Dan ________________________________________________________________________________________ It goes without saying that .