A tessellation is a pattern formed by the repetition of a single unit or shape that, when repeated, fills the plane with no gaps and no overlaps. Use these websites to learn more about tessellations and to create your own tessellations.
Totally Tessellated! Click on the "Enter the Site" link at the top of the page. Note the links to History, Essentials, Escher, Mosaics/Tilings, and Beyond.
Newton's Workshop - Tessellation Tool This tool allows you to build tessellations and other designs by attaching the corners of various shapes to one another.