[Added November 1997]
I have read the book Born in a blue day by # Daniel Tammet. Daniel Tammet has a mild form of autism called Asperger’s syndrome and reports in this extraordinary book how he was able to memorise in a few weeks the first 22,000 digits of pi and then recall them in around 5 hours before a jury that checked the correctness of each digit. As with Luria’s mnemonist the secret seems to be synaesthesia. Daniel sees each digit as a distinct pattern : for example the 9 is blue and tall. To him a string of 10 random digits is like a landscape. In the book he makes some sample drawing of this peculiar landscape that he sees in the mind. What he has done is to build little by little a huge landscape in his mind representing all the 22,000 digits of pi.
In the day of the recall he had only to concentrate himself on the features
of this extraordinary mental painting extracting one by one all the pi digits.