See also: https://www.pouet.net/prod.php?which=89362 -- https://www.youtube.com/watch?v=zprSxCMlECA

A demo, including music and graphics, written for the 1541 disk drive -- no, it is not a C64 demo, it runs entirely on the 1541 (which has a 6502 CPU and some amount of RAM in it)