Sonic Pi, the live music coding environment, has a circular list structure type called a 'ring'. This proves curiously helpful for a bunch of musical scenarios.

Sonic Pi, the live music coding environment, has a circular list structure type called a 'ring'. This proves curiously helpful for a bunch of musical scenarios. Like: - you can put a short chord sequence into a ring, and it now functions as a list of as many repetitions of that chord sequence as you like. You can just loop over it forever (which is kind of the essence of how sonic pi live-loop play works) - you can put the notes that make up a scale into a ring, and use it to extract specific chords - like, take the 1st, 3rd, 5th, 7th and 9th note - from just a seven note scale. - you can use rings of booleans to capture drum patterns and rings of notes to capture melodies, and loop them forever - etc. etc.