Prime Beats
Music generally repeats itself, though something in 4/4 time (like nearly all pop music) repeats with more regularity than anything that uses prime numbers of any notable size. The following (which stops mercifully short of the full least common multiple) plays 3 against 5, 7, 11, and 13, with pitches picked somewhat at random resulting in a 5-20 pitch set or here D Eb A Bb G.
It might be good to fall asleep to, I guess?
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