This demo includes two windows.

The window "Curve: X(t)" displays the curve X(t). Several example curves are provided to enter in the control window as in earlier demos.

The window "Perturbed Tangential Image" displays the tangent vector T(t0) and a curve that it traces out. The tangent vector is perturbed slightly so that the curve that it traces out does not overlap itself.

The rotation index is the total change of direction angle from tmin to tmax divided by 2π, which is visualized in the "Perturbed Tangential Image" window.

Change the value of t0 and other variables as in earlier demos.
As in earlier demos, there are "Show entire curve" and "Show Color Spectrum" options.