A new puzzle every day: the board for the cover puzzle from Issue 23
More from Chalkdust
NEW! Pop-math book club
Do you have lots of unread pop math books on your shelves? Join our new monthly online book club!
Things to make
Platonic shapes from tube maps, flexagons, and more mathematical craft
What’s hot and what’s not
Optimal Pac-Man
Ghostbusting with graph theory
Reinventing 2D
What a difference a matrix makes
Your social networks
How similar are you to your friends?