When I multiply numbers together, I see two shapes. The image starts to change and evolve, and a third shape emerges. That's the answer. It's mental imagery. It's like maths without having to think.

I'm inconsistent because I'm human.

We know next to nothing with any certainty about Pythagoras, except that he was not really called Pythagoras. The name by which he is known to us was probably a nickname bestowed by his followers. According to one source, it meant ‘He who spoke truth like an oracle’. Rather than entrust his mathematical and philosophical ideas to paper, Pythagoras is said to have expounded them before large crowds. The world’s most famous mathematician was also its first rhetorician.

I had eventually come to understand that friendship was a delicate, gradual process that mustn’t be rushed or seized upon but allowed and encouraged to take its course over time. I pictured it as a butterfly, simultaneously beautiful and fragile, that once afloat belonged to the air and any attempt to grab at it would only destroy it.

Fischer, the great American chess champion, famously said, 'Chess is life.' I would say, 'Pi is life.'

My algebra was relatively poor. I found it very difficult to use equations that substituted numbers - to which I had a synesthetic and emotional response - for letters, to which I had none. It was because of this that I decided not to continue math at Advanced level, but chose to study history, French and German instead.

It was hard for me to find my voice because I was, for so long, absorbed in my own world.