This week we build some self-intersecting Boy surfaces:

http://teach.hilderbuild.com/tiki-index.php?page=Paper%20Boy%27s

http://www.southernct.edu/~fields/topology/Boys_surface.html

Polyhedral versions:

http://plus.maths.org/content/os/issue27/features/mathart/index

http://www.savoir-sans-frontieres.com/JPP/telechargeables/English/Topo_the_world_eng.pdf page 48 (the Topologicon is available in many languages besides English)

http://www.southernct.edu/~fields/topology/Boys_surface.html

The greatest thing since sliced bread.

http://michelle.esfm.ipn.mx/~mrspock/slice/

Enjoy! We’re starting with this post a brand new column “Handy Math” – it’s dedicated to Professor Feynman of course.

PS Yes dear readers, watch for another new column later in the week.