They, plus Ben and Chris, win a copy of our New Scientist puzzle book Headscratchers. The back pages Mathematics of life WHEN solving problems in the real world, it is rare that the solution is purely mathematical, but maths is often a key ingredient. These articles are posted each week at newscientist.com/maker Rob Eastaway (left) is a maths author; Brian Hobbs is a puzzle podcaster. [Extracted from the article]