As a grapheme to colour synaesthete, I have no idea how this visual image from 2009 published in New Scientist might relate to the number Pi. Might it make any sense as a mnemonic image? Might it just be a bit of nonsense?
Savant art: a window into exceptional minds. New Scientist. June 3rd 2009.
[a gallery of pictures of savant art with a work by Tammet at the beginning, which is supposed to be a representation of Tammet’s synaesthesia mental visualization of the number Pi.]