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 each pair of opposite edges (-5[2])of the unit square (-5[1])in the same direction. (-5[1])This orientable (10[1])surface (-5[1])with Euler characteristic zero is the Cartesian product of two circles. (-5[1])Depending on orientation, either a Klein bottle or this genus-one surface is formed (-5[2])by joining the circular ends of a cylinder. (10[1]-5[1])For 10 points, the surface of a coffee cup is topologically equivalent to what single-holed (10[1])surface shaped like a doughnut? ■END■ (10[8])