Where is the center of a sphere? If the sphere is considered as an everyday object embedded in our universe, the answer may take a form such as “at the intersection of two diameters,” or, pointing at it dramatically, saying with particular emphasis, “There! In the middle, in the interior!” See figure 9. If, though, we consider the surface of the sphere as a manifold, as a space in itself and of itself, then the question and answer are subtler. As in the case of our universe, as if we were points residing in the sphere itself, there is no legitimate referral to a point outside the universe of the surface of the sphere. There is only the sphere; every thing else is no thing. Where is the center of a sphere? Considered as a manifold, then, the answer is Everywhere and nowhere.