## Articles

*any*tilings based on fiveness?

**Craig Kaplan**takes us through the five-fold tiling problem and uncovers some interesting designs in the process.

**Chris Sangwin**takes us through excerpts of Euler's algebra text book and finds that modern teaching could have something to learn from Euler's methods.

**Chris Sangwin**tells you how to make your own set of

*Napier's bones*and perform mathemagic with an interactive checker board.

**Phil Wilson**continues our series on the life and work of Leonhard Euler, who would have turned 300 this year. This article looks at the calculus of variations and a mysterious law of nature that has caused some scientists to reach out for god.

**Abigail Kirk**explores one of the formulae that carry his name.

**Tom Körner**'s explanation really is a piece of cake, served up with a hefty estimate of pi.