This very useful site allows you to change the color and background patterns of a web page, and then copy the HTML code to your own site. Includes a tutorial, links to other web pages about color design, and links to a TableMaker and a...

Chinese-language Java applet illustrating Fermat's principle that light follows the fastest path between any two points. Excellent animation and accompanying text. Relates Fermat's principle to Snell's law.