This demo displays the several example functions of simple curves.
A curve is simple if it does not intersect itself, except in the case of
a closed curve it intersects itself at X(t0_min)=X(t0_max).
To change which funtion is viewed,
type the function title into the definition of X(t). For example, X(t)=ellipse(t).
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.