D.1. - Plane curves
The command file curves displays 12 curves, each in a small window. The data for the curves is supplied by the user function curves.2, which generates plane curves using formulas taken from Standard Mathematical Tables (Cleveland, CRC Press, 1976).
The command file curves calls another command file, curves.p1, which is nested and is called with four arguments. The first two values specify the location of the small windows. The next two arguments, each of which is enclosed in quotes, set the parameters for the function curves.2. The third argument gives the range of the type 2 user function parametric variable, while the fourth selects and parameterizes the particular curve.