What does "twisted" mean?

Twisted: Contorted; crooked spirally; subjected to torsion; hence, perverted. Twisted curve (Geom.), a curve of double curvature. See Plane curve, under Curve. -- Twisted surface (Geom.), a surface described by a straight line moving according to any law whatever, yet so that the consecutive positions of the line shall not be in one plane; a warped surface.