After building the graphic equaliser demo, I noticed that you could see distinctive frequencies appearing when some of the chords were played, so I thought I'd build a heat-map to show up which frequencies were being played most often. It's a bit slow to start off, but towards the end it starts to get really colourful and pretty.
The further down the rainbow the colour is, the more the note has been played :)
Requires FireFox 4 beta. Other browsers will eventually catch up. I believe that there's a patched webkit version which will run this, but I'm not sure where to find it.
Music: Unt by Cubic