You've probably seen them many times, but never knew what they were called.

Of if you've heard the term tessellations, you may only be familiar with the somewhat surreal renderings of the legendary M.C.Escher, whose designs decorate many a college student's living space.

For those who have never heard of this rare form of art, tessellations are designs featuring animals, birds, etc, which fill a page without overlapping to form a pattern.

A site, Tessellations.org maintained by David Annal, who himself has created a number of compelling patterns using tessellations, celebrates their unique history.

The Galleries area includes Annal's own designs, a number of tessellations by Escher, and a few submitted by visitors to the site.

If you're an aspiring artist, take a look at the instructional section and try your hand at making some yourself!