Kunal Anand, who has also developed the del.icio.us graph featured in VC, produced a series of graphs that aim at visualizing alternative song structures with Graphviz. These horizontally extended visualizations are based on previous/next words of some of Kunal's favorite songs.
As he wrote on his blog: "I am interested in comparing some of these alternative song diagrams to more radio/poppy ones. I might even try looking at all the tracks of an album too. (...) I am leaving all the analysis to your interpretation. After all, music is an art. I am merely curious if it is possible to visualize a possible hit".
The first image represents the song structure of Falling Away From You by Muse, while the second portraits a detail view into A Day in the Life by The Beatles.