Back in 1979 I wrote a Z80 machine language program on a TRS-80 Model I[0] to implement the Pollard Rho algorithm[1] and explore factoring repunits[2]. To monitor it I would put an AM radio next to the machine and listen to the noise.<p>The "Run around the loop" phase made a Chuntering[3] noise, and then the GCD[4] phase, implemented via Euclid's Algorithm[5] made a wonderfully ascending whoosh!<p>It was fairly straight-forward to know where the code was, and what it was doing, and it was great to fall asleep to of an evening.<p>================<p>[0] <a href="https://en.wikipedia.org/wiki/TRS-80" rel="nofollow">https://en.wikipedia.org/wiki/TRS-80</a><p>[1] <a href="https://en.wikipedia.org/wiki/Pollard%27s_rho_algorithm" rel="nofollow">https://en.wikipedia.org/wiki/Pollard%27s_rho_algorithm</a><p>[2] <a href="https://en.wikipedia.org/wiki/Repunit" rel="nofollow">https://en.wikipedia.org/wiki/Repunit</a><p>[3] <a href="https://dictionary.cambridge.org/dictionary/english/chuntering" rel="nofollow">https://dictionary.cambridge.org/dictionary/english/chunteri...</a><p>[4] <a href="https://en.wikipedia.org/wiki/Greatest_common_divisor" rel="nofollow">https://en.wikipedia.org/wiki/Greatest_common_divisor</a><p>[5] <a href="https://en.wikipedia.org/wiki/Greatest_common_divisor#Euclid's_algorithm" rel="nofollow">https://en.wikipedia.org/wiki/Greatest_common_divisor#Euclid...</a>