This demo includes two graphical display windows.

The window "Curve: X(t)" displays the curve X(t) (which is by default a
planar curve), the point X(t_{0}), the unit tangent and
principal normal vectors T(t_{0}) and
P(t_{0}), and the vector U(t_{0}) obtained by rotating
T(t_{0}) 90 degrees counterclockwise, with the tails of these
three vectors at X(t_{0}). Note how U(t_{0}) compares
to P(t_{0}).

The window "k(t)" displays the graph of the curvature k(t).

You can change t_{0} and X(t) in the control window. The
control window
includes a list of functions that you can use for X(t), along with
parameters used to define those functions.

As in previous demos there is a "Show Color Spectrum" checkbox.