Jay Kennedy of Britain's University of Manchester posits that Plato composed his dialogues "according to a 12-note
musical scale, attributed to Pythagoras," Julian Baggini reports in The Guardian . . . http://www.guardian.co.uk/world/2010/jun/29/plato-mathematical-musical-code
. . . which prompts Tom Service, The Guardian's classical-music blogger, to survey composers, from Bach to John Zorn, who've coded their music numerically:
http://www.guardian.co.uk/music/tomserviceblog/2010/jul/01/composers-clandestine-codes-plato
One of the catchiest, yet bummer, numbers in music is the minor third. Research by Meagan Curtis of Tufts University's Music Cognition Lab finds that this interval conveys sadness in both music and speech. Ferris Jabr reports in Scientific American:
http://www.scientificamerican.com/blog/post.cfm?id=music-and-speech-share-a-code-for-c-2010-06-17
CAUTION: Do not try to make Pythagorean sense of that graphic. Chaos theory might work, though.