Lunus Sakesson's 256 byte Commodore 64 demo "A Mind Is Born" took first place at the Oldskool 4K Intro compo at the Revision 2017 digital art festival. From his program notes:
The demo is driven by its soundtrack, so in order to understand what the program needs to do, it helps to have a schematic overview of the various parts of the song.
The three voices of the SID chip are used as follows: Voice 1 is responsible for the kick drum and bass, Voice 2 plays the melody and Voice 3 plays a drone that ducks on all beats, mimicking the genre-typical side-chain compression effect.
All in all, the song contains 64 bars in 4/4 time. It is played back at 112.5 bpm by means of a 60 Hz timer interrupt. The interrupt handler is primarily responsible for music playback, while the visuals are mostly generated in main context.
"A Mind Is Born" by Linus Akesson