The window "Tangential Indicatrix" displays the path of the tangent vector on a transparent sphere.
As in earlier demos, there are "Show Color Spectrum", and "Show Entire Indicatrix" checkboxes.
The partialcurvature readout displays the total space curvature of the curve from t0_min to t0. The totalcurvature readout displays the total space curvature of the entire curve.
Fenchel's Theorem tells us that the total curvature must be at least 2π.