Diagram showing the bridges in Königsberg. If you have not seen this puzzle before, you may like to try to find a route crossing them all exactly once before reading on.
Bridges of Koenigsberg
More from Chalkdust
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?
Art meets maths