For the uninitiated, the Commodore 1541 (and later 1570) are external floppy drives that contain their own 6502 CPU and work RAM. In fact, you could daisy-chain two of them with a C64, tell one to copy a whole disk from the other, and disconnect the C64; the drives would continue to work as they do not rely on the C64 at all.
The "C64" demo "Freespin" wires the drive's data cable directly into the monitor's data cable to play a demo (including audio!) without an actual C64 involved at all:
