Daniel Tammet has some pretty impressive synaesthetic abilities. From Born on a Blue Day: > I never write anything down when I'm calculating, because I've alwa

Daniel Tammet has some pretty impressive synaesthetic abilities. From Born on a Blue Day: > I never write anything down when I'm calculating, because I've always been able to do the sums in my head and it's much easier for me to visualise the answer using my synaesthetic shapes than to try to follow the `carry the one' techniques taught in textbooks we are given at school. When multiplying, I see the two numbers as distinct shapes. This image changes and a third shape emerges --- the correct answer. The process takes a matter of seconds and happens spontaneously. It's like doing maths without having to think. > [...] I'm multiplying 53 by 131. I see both numbers as a unique shape and locate each spatially opposite the other. The space created between the two shapes creates a third, which I perceive as a new number: 6943, the solution to the sum. [sic]