The hyperbolæ $XY = 1$ and $XY = n$.
More from Chalkdust
Things to makePlatonic shapes from tube maps, flexagons, and more mathematical craft
What’s hot and what’s not
Optimal Pac-ManGhostbusting with graph theory
Reinventing 2DWhat a difference a matrix makes
Your social networksHow similar are you to your friends?
Art meets maths