Your geometry puzzle for the day involves a Stieglitz photo of a sculpture that may be by Duchamp (or maybe by a female friend of Duchamp from whom Duchamp stole the glory, that's not the point):
It was created by rotating a commercial urinal from its usual position.
Assuming that the photo is from where you would stand in front of either object, by what angle was it rotated, around what axis?
Why? Because we've been arguing about it on Wikipedia, of course, why else?