## 16

*Plus*talks to

**Christine Hogan**, programmer, sysadmin and author, now studying aerodynamics and hoping to become a member of a Formula One team.

**Imre Leader**looks at the colourful world of Ramsey Theory.

**Bill Casselman**writes about the intriguing amateur mathematician Henry Perigal, who took his elegant proof of Pythagoras' Theorem literally to his grave - by having it carved on his tombstone.

**Alison Boyle**investigates aperiodic tilings, which have had unexpected applications in describing new crystal structures.