This demo includes two graphical display windows.

The window "Curve: X(t)" displays the curve X(t) and the point X(t0).

The window "kg(t)" shows a graph of kg(t) and the point (t0, kg(t0)). Note that, as stated in the Four-Vertex Theorem, there are always at least four critical points of kg(t).

Change the value of t0 and other variables as in earlier demos.
As in earlier demos, there is the "Show Color Spectrum" option.