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.

I did have a very restricted, regimented life. There was a kind of happiness there, a contentment, but it was a small happiness within very clear and delineated borders.

Moment by moment throughout our lifetime, our brains hum with the work of making meaning: weaving together many thousands of threads of information into all manner of thoughts, feelings, memories, and ideas.

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.

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

I recited Pi to 22,514 decimal points in five hours and nine minutes. I was able to do this because of weeks of study, aided by the unusual synaesthesic way my mind perceives numbers as complex multidimensional coloured and textured shapes.

When I achieved the European record for reciting pi in 2004, this captured the imagination of Professor Simon Baron-Cohen in Cambridge and he finally diagnosed me with Asperger's that year.