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.

My autism is a very mild form. It was diagnosed at the age of 25, partly because it wasn't diagnosable as a teenager (this is Asperger's syndrome, specifically). But there were certainly traits within that condition, within the autism spectrum in general, especially at the high functioning end, that I think are best looked at as pluses.

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

The human brain is like a memory system that records every thing that happens to us and makes intelligent predictions based on those experiences.

Why learn a number like pi to so many decimal places? The answer I gave then as I do now is that pi is for me an extremely beautiful and utterly unique thing. Like the Mona Lisa or a Mozart symphony, pi is its own reason for loving it.

There are estimated to be fewer that 50 prodigious savants worldwide. If we were brought together, it would be disappointing in the sense of us having different abilities. One thing that would make me feel united with them would be the sense of us having grown up in isolation.

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.