The window "Curve: X(t)" in this demonstration displays the curve X(t)
= (cos(t), sin(t), cos(2t)/c), the point X(t0), and the
normal vector, P(t0).
The window "Spherical Image of P(X)" P on a transparent sphere, and the principal indicatrix. From
Jacobi's Theorem, if the principal indicatrix is a simple curve, it
will divide the sphere into two equal area regions.
As in earlier demos, there are "Show Color Spectrum", and "Show Entire Indicatrix" checkboxes.