This series of Axolotl and Tuatara cartoons is based on an interview with Susan Bryant, an emeritus research professor at UC Irvine. If you’d like to read more about the polar coordinate model of limb regeneration, please check out the links below:
http://regeneration.bio.uci.edu/
http://10e.devbio.com/article.php?id=184
http://www.ncbi.nlm.nih.gov/books/NBK9971/