SPECTRO

A swirling flow shaped partly by the spectrogram, so the music's own past steers the picture.

The flow runs along the contours of a smooth landscape, which is what makes it swirl without ever gathering into one place or leaving an empty patch. The landscape is slow noise with the spectrogram laid over it: across the screen is the spectrum, low on the left, and distance from the middle line is how long ago. Loud moments of the last few seconds become hills the flow circles round.