looking for specific recreational math puzzle book Long time ago, I read a (recreational) math puzzle book and I remember was that in the pocket book there was a puzzle where the parents of a worm were deciding how big the blanket for their baby worm should be. (so he would not catch a cold), The first idea that they needed a blanket of area $2 \pi l ^2 $ ($l$ being the length of baby worm) ,but after some intriguing maths they came to the conclusion they could do it with a blanket of size $0$nor something like that. Like often :( I forgot the name of the book but want to buy a new copy. Anybody recognize the puzzle and can tell me which book it was?

It's a book by Ian Stewart: _Game, Set and Math_. The chapter was an adaptation of his column for _Scientific American_ in January 1996.