Thank you... Thank you... Thank you!

Many of these materials would have been in my mental trashcan without the intervention of Pat Donahue and Lori Thompson who gave me new perspective by sharing their ideas.

Doug Shaw provided editing support and comic relief. Anna Gardberg's edits and suggestions for revisions were also quite valuable. Tamara Munzner directed me to some great resources and showed "Penumbral Shadows", which contains the first hypercube animation I (sorta) understood.

The Geometry Forum is an online math and education mecca which led me to some great people whose e-mail provided more suggestions for this unit: Thanks Mark Saul and Tom Farrell!