1-Bit Symphony (2010) by Tristan Perich is a music album released as a small electronic object inside a CD case. Instead of containing an actual CD recording, the case holds a hand-assembled circuit and a microchip that plays the piece live through a headphone jack.

The whole composition is built using 1-bit audio, the simplest form of digital sound, just on and off signals. I love this example because the format, the technology, and the composition are all the same thing.

[Video source]