| Solving the Ladder Problem on the
Back of an Envelope. Mathematics Magazine, Volume 80, Number 3, June 2007, pp 163 - 182. |
| Doug Ensley's
Family of Curves and Envelope Applet |
| Combined Ellipse and
Line Applet for Astroid |
| Uncommon
Mathematical Excursions: Polynomia and Related Realms |