Thinking in pictures

High-functioning autistic-savant, Daniel Tammet, author of memoir Born on a Blue Day, describing what the world of numbers looks like:

Every number to me is beautiful. Every number has its own shape, its own color, its own texture. Thirty-seven, to give an example, is a lumpy number, lumpy like oatmeal. Eighty-nine is soft and flowing, like snow. A number like one-one-one would be very bright and shining. When I look at a very long series of numbers, like pi, for example ... for a number of that size, what I'm doing is I'm pulling all the colors and shapes and textures I see in the individual numbers together and the result is a visual landsacpe -- a number-scape in my mind's eye. It's full of color, texture; it's beautiful. It's like a second country -- a country of the mind.

From an interview on To the Best of Our Knowledge (PRI and Wisconsin Public Radio).

Tammet is also quite gifted with languages. I wonder if language is visual for him as well.