- An ellipse is specified in the control window and displayed in the "Cylinder & Ellipse" window.
- A red line is specified in the "Domain" window by moving the white hotspot and changing the angle by changing alpha in the control window.
- The image of this line is displayed in red on the cylinder.
- A plane is diplayed in light gray that is determined by the tangent vector to the image of the white hotspot along the red curve, and also by an angle theta chosen in the control window.
- The intersection of this plane and the cylinder is an ellipse displayed in green.
- Readouts in the control window give the normal curvature, geodesic curvature, and geodesic torsion of the green ellipse at the white point.
- Readouts in the control window give the normal curvature,
geodesic curvature, and geodesic torsion along the whole green ellipse.