Algebraic varieties named for this shape are subject to the orbit–cone correspondence and can be constructed from fans. For knots named for this shape, “x-to-the-p equals y-to-the-q” is a relation of the knot group. “R-squared” quotient “Z-squared” is isomorphic to this surface, which has “Z-cross-Z” as its fundamental group. This surface can be obtained by gluing (-5[1])each pair of opposite edges of the unit square in the same direction. (-5[1])This (-5[1])orientable (10[1])surface with Euler (-5[1])characteristic zero is the Cartesian product of two circles. Depending on orientation, either a Klein bottle or this genus-one (-5[1])surface (-5[1])is formed by joining the circular ends of a cylinder. For 10 points, the surface of a coffee cup is topologically equivalent (10[1])to what single-holed (-5[1])surface (10[1])shaped like a doughnut? ■END■ (10[6])