Daniel Tammet is quite normal to listen to and look at. But he can memorize a ridiculous part of the string of numbers of the number pi. Besides that, it is proven that he can learn a very hard language in just one week. What’s incredible about this talent, is that he just sees the answers appear before his eyes. He doesn’t conscientiously calculate the very hard calculations he does, but visualizes them in mental landscapes. Daniel has Synesthesia, which is a ‘condition’ that causes the people that have it to mix up different sorts of sensual input, like sound, color, shape and other perceivable phenomena.
His case goes against most current theories on how the human mind works, because his calculations seem to be done in his subconscious, in an intuitive way.