A plane curve also called the Peg Top and given by the Cartesian equation

(1) |

(2) | |||

(3) |

for . It was studied by G. de Longchamps in 1886. The generalization to a Quartic 3-D surface

(4) |

**References**

Cundy, H. and Rollett, A. *Mathematical Models, 3rd ed.* Stradbroke, England: Tarquin Pub. p. 71, 1989.

Lawrence, J. D. *A Catalog of Special Plane Curves.* New York: Dover, pp. 148-150, 1972.

Nordstrand, T. ``Surfaces.'' http://www.uib.no/people/nfytn/surfaces.htm.

© 1996-9

1999-05-25