<[Alan]> > if you go straight long enough you wind up where you were There's this story in Martin Gardner's "Aha! Gotcha" about a space traveler who follows the geodesic all the way back to the point of departure. Not only that, but his universe is a non-orientable manifold (think 4d mobius strip) so he's now a mirror image of his original self...his heart is on the wrong side.