## Articles

Over the last few years the words string theory have nudged their way into public consciousness. It's a theory of everything in which everything's made of strings — or something like that. But why strings? What do they do? Where did the idea come from and why do we need such a theory? David Berman has an equation-free introduction for beginners.
How does complexity arise from simplicity?
John Napier was a clever man indeed. Besides inventing the logarithm, he developed ingenious calculating devices that fully exploit the power of the positional system. In this article 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.
Leonhard Euler, the most prolific mathematician of all time, would have celebrated his 300th birthday this year. In this article, the second in a four-part series on Euler and his work, Abigail Kirk explores one of the formulae that carry his name.
You might know the famous formula for an area of a circle, but why does this formula work? Tom Körner's explanation really is a piece of cake, served up with a hefty estimate of pi.
One of the many strange ideas from quantum mechanics is that space isn't continuous but consists of tiny chunks. Ordinary geometry is useless when it comes to dealing with such a space, but algebra makes it possible to come up with a model of spacetime that might do the trick. And it can all be tested by a satellite. Shahn Majid met up with Plus to explain.
If you've ever redecorated a bathroom, you'll know that there are only so many ways in which you can tile a flat plane. But once you move into the curved world of hyperbolic geometry, possibilities become endless and the most amazing fractal structures ensue. Caroline Series and David Wright give a short introduction to the maths behind their beautiful images.