The window "Curve: X(t)" displays the curve X(t), the point X(t0), a point P with its position vector, and a unit circle centered at the origin. You can drag the point P along the unit circle shown in the window.

The window h(t) shows a graph of the height function h(t) = X(t)*P.

Change the value of t

As in earlier demos, there is the "Show Color Spectrum" option.