## Articles

Are the unchanging features of the Universe really unchanging?

**Oli Freke**has always been fascinated by sine waves, so much so that he's created a song based on them for the Geekpop festival, which is currently taking place on the Web. In this article he explores his song, touching on ancient Greek mythology, strange piano tunings and Johann Sebastian Bach.

**Jerry Gollub**tells

*Plus*about a new discovery which combines experiment with sophisticated maths.

**Carola Schönlieb**explores how mathematicians use the heat equation to fill in the gaps.

**David Spiegelhalter** and **Mike Pearson** explore how risk can be spun and there's an interactive animation for you to have a go yourself.

**Phil Wilson**looks at

*constructivist mathematics*, which holds that some things are neither true, nor false, nor anything in between.

**Angus Brown**looks at one of these, a simple model for option pricing, and explains how it takes us on the road to the famous Black-Scholes equation of financial mathematics, which won its discoverers the 1997 Nobel Prize in Economics.