This demo includes one graphical display window that shows the curve
X(t) and the point X(t0).
The control window displays the arclength L of X(t), the area A
enclosed by X(t) if X(t) is a simple curve, and the ratio L2/4πA,
which is always greater than or equal to 1 according to the
Change the value of t0 and other variables as in earlier demos.
As in earlier demos, there are "Show entire curve" and "Show Color Spectrum" options.