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.