Incredible Art
1, 2, and 3-Point Perspective
Introduce drawing young scholars to perspective with a series of lesson plan that detail how to draft images in one-, two-, and three-point perspective. Each exercise includes step-by-step, illustrated directions and examples.
Wolfram Research
Wolfram Math World: Semiregular Tessellations
This one page Mathworld site has a number of examples of semiregular tessellations. A definition and a small amount of related information is given at the bottom of the page.