A space named for this mathematician is the simplest nontrivial fiber bundle of an interval over S1 (“S-one”); a quotient space description of that space is as a torus over the group action of the symmetric group on two letters. This mathematician names transformations of the complex (10[1])plane with the form (10[1])“az-plus-b over cz-plus-d,” (10[1])as well as a function equal to zero for any number with a squared (-5[1])prime factor. Attaching the edges of an Euler characteristic-zero surface named for this mathematician to itself forms the real projective plane, while joining two (10[1])copies (10[1])of that non-orientable surface along their boundaries (10[1])creates a Klein bottle. For 10 points, twisting a piece of paper and gluing its (10[1])ends together (10[1])creates what German mathematician’s one-sided “strip”? (10[1])■END■