I've been lurking around all week feeling very much under the weather with the flu but reading the postings for the midle school group. I just went to the intro page for tessellations and explored the Other Tessellation Links and Related Sites page. I found one sight that was not working and it reminded me that I had heard there were commercial programs that would search your pages for expired links but wondered if any one knew of a shareware program of that type.
The sight in question is Tessellation Intro - Univ. of Minnesota - Math 5337 Final Project Cecilia Donarski, Bob Hazen, Kristin Lee, Aki Yoshino I found the sight for the course by backing up in the url and they list this project as one for a previous summer but don't have a connection to it so it must have been taken off the web (at least at the UMN sight)