For those who enjoy the design aspects of quilting, tessellations offer some fantastic possibilities, from simple to sublime. Tessellations are designs that interlock and repeat, like Tumbling Blocks, Thousand Pyramids, or my avatar. M.C. Escher was a master with tessellations, and I once saw a quilted interpretation of one of his works. It was incredible!
This website offers history, basic knowledge, design grids you can print and color, and examples. The link is to the main page and you will need to explore thru the menu at the top of that page.
http://library.thinkquest.org/16661/index2.html
This site is interactive and is great fun. You can design online, print and even save your work. It has lots of options and is quite user friendly.
http://gwydir.demon.co.uk/jo/tess/index.htm
I hope someone finds them as useful as I have. Enjoy! :-)