The term "twisted sphere" is used to mean either a projective plane (Henle 1994, p. 110) or the corkscrew surface obtained by extending a sphere along a diameter and then twisting (Gray 1997, p. 477).
Twisted Sphere
See also
Corkscrew Surface, Projective PlaneExplore with Wolfram|Alpha
References
Gray, A. Modern Differential Geometry of Curves and Surfaces with Mathematica, 2nd ed. Boca Raton, FL: CRC Press, 1997.Henle, M. A Combinatorial Introduction to Topology. New York: Dover, 1994.Referenced on Wolfram|Alpha
Twisted SphereCite this as:
Weisstein, Eric W. "Twisted Sphere." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/TwistedSphere.html