There is a nifty new visualisation tool for ‘visualising repetition in MIDI files’ called The Shape Of Song.
What does music look like? The Shape of Song is an attempt to answer this seemingly paradoxical question. The custom software in this work draws musical patterns in the form of translucent arches, allowing viewers to see–literally–the shape of any composition available on the Web. The resulting images reflect the full range of musical forms, from the deep structure of Bach to the crystalline beauty of Philip Glass.
You can view (and hear) a stack of MIDI files on the site or you can point it at an URL containing a MIDI file. Already it has been overrun with Def Leppard and Tool.