. "hyperboloid of two sheets" . . . . . . "hyperboloid" . . . . . "hyperbolic" . . "thought of as a sphere" . . . "hyperbolic-shaped" . "unit quasi-sphere" . . . "Hyperboloid#Two sheets" . . "Hyperboloid of two sheets" . "Hyperboloid of one sheet" . . "hyperboloids of revolution" . "Hyperboloid" . . . . "hyperboloid of revolution" . . "hyperboloid of one sheet" . . "Hyperboloid" . .