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 (10[2])with the form (10[1])“az-plus-b (10[1])over (10[1])cz-plus-d,” (10[2])as well as (10[1])a function equal to zero for any number with a squared (-5[1])prime (10[1])factor. (10[1])Attaching the edges of an Euler characteristic-zero (10[1])surface named for this mathematician (-5[1])to itself forms the real (10[1])projective (10[1])plane, (10[2])while joining two (10[1])copies (10[1])of that non-orientable (10[1])surface (10[1])along their boundaries (10[3])creates a (10[1])Klein bottle. (10[1])For 10 points, (10[2])twisting (10[1])a piece of paper (10[2])and gluing (10[3])its (10[1])ends (10[1])together (10[1])creates what (10[1])German mathematician’s one-sided “strip”? (10[1])■END■ (10[1])