Make Your Own Ruled Surface
A ruled surface is a surface that has a parametrization of the form , where is the directrix and the director curve or ruling. Such a surface can be generated by the continuous motion of a straight line in space. Here you can choose to be a constant multiple of one of the functions , , and ( is the constant) and to be a constant multiple of one of the functions , , and ( is the constant). Ruled surfaces occur in architecture.
The snapshots show some well-known ruled surfaces.
Snapshot 1: right conoid
Snapshot 2: Plücker's conoid
Snapshot 3: helicoid
 W. L. Edge, The Theory of Ruled Surfaces, Cambridge: Cambridge University Press, 1931. www.maths.ed.ac.uk/cheltsov/edge2013/pdf/ruled.pdf.
 O. Knill. "Math21a Fall 2009, Gallery of Ruled Surfaces." (2009) www.math.harvard.edu/archive/21a_fall_09/exhibits/ruled/gallery1.html.
 A. Gray, "Ruled Surfaces," Modern Differential Geometry of Curves and Surfaces with Mathematica, 2nd ed., Boca Raton, FL: CRC Press, 1993 pp. 431–456.