Supplies Java-animated interactive pictures of constant perimeter and area rectangles.

Erich packs a variety of geometric shapes inside square packaging. Includes equations for each image.

Learn about a Windows application that transforms and distorts images. Includes news, downloading information and a feedback form.

Take a look at interactive graphs created by Java applets that represent mathematical ideas. Includes details about Pythagoras' theorem.

Visual geometrical dictionary of concepts and properties of plane curves, such as cusps, tangents and evolutes.