University of Illinois
University of Illinois Urbana Champaign: Egg Math Axis of Symmetry
Uses an egg to demonstrate the concept of axis of symmetry. Put your cursor over the picture to "move" around the egg. Offers links to related concepts, including Cartesian Ovals and Ovals of Cassini.
University of St. Andrews (UK)
University of St. Andrews: Cartesian Oval
This University of St. Andrews page offers an illustration and equation for the Cartesian Ovals, sometimes called the "Ovals of Descartes" for their discoverer, Rene Descartes.
University of Illinois
University of Illinois Urbana Champaign: Chickscope Eggmath: The Shape of an Egg
An interactive page offering a view of a rotating egg, information on rotational symmetry, and definitions of related topics.