More from Chalkdust
- Books, business and barns are the topics readers have sent in to the professor's postbox this issue
- Stephen Muirhead meets neither, as he explores waves, tiles and percolation theory
- Robert J Low flips one upside down.
- A polygon with four and a half sides?!
- Are you a winner?
- Here is a very exciting way to measure how similar is your music playlist between your friends, or how similar are your Facebook contacts.