sarah-marie belcastro is a free-range mathematician and a guest faculty member at Sarah Lawrence College. Her primary mathematical research area is topological graph theory. Among her many non–pure-mathematics interests are the feminist philosophy of science, dance (principally ballet and modern) and changing the world. She received her Ph.D. from the University of Michigan. Her most recent book is Discrete Mathematics with Ducks (AK Peters, 2012). For more information about her work, including her mathematical knitting, visit her website, www.toroidalsnark.net. She can also be found on the knit and crochet social-networking website Ravelry as smbelcas. Address: 278 Bay Road, Hadley, MA 01035. E-mail: smbelcas@toroidalsnark.net.