You have only to enter two functions *f* (t) and *g*(t) defining the
parametric curve, with ranges of variation for *t*, *x*, *y*.
You will receive as reply an animated sequence showing the curve with a
moving point corresponding to the variation of the parameter *t*. This
variation of *t* is shown by a bar at the bottom of the figure,
synchronized with the point on the curve.

Some examples of parametric curves are at your disposal.