One of the Stanford Gardner (let's face it) Celebration talks was geography trick questions, several of which are in http://boards.straightdope.com/sdmb/showthread.php?t=233928 (e.g., the border of Colorado is a (spherical) n-gon, where n = ___.) This page also has *------------Paul>Name the three states that have parts of a perfect circle in their borderlines. If you want the answer, you have to tell me how to do a spoilers box.* Gest>Admit it; there *is* no third and you only put it in so someone would tell you how to do a spoiler box! Well it worked. Just enclose the *spoilt* text in vB code spoiler tags as you would any other kind of text. ------------- To an off-list discussion, NeilB added BG>Real, honest to God legally defined circles. NB>...with a radius less than a thousand miles. Otherwise, every latitude line would count as a circular arc whose center is at the North (or South) pole. --Neil (And longitudes are circles concentric with Earth itself. --rwg Well, not really. Is the Earth legally defined as a sphere anywhere?) Neil then ferreted out *five* states with legitimate circular arcs! Colorado spoiler. n=π⁴/ζ(4)/15 . --rwg