It turns out the Spirograph patterns I’d been using to wring out the MPCNC are also known as Guilloché, perhaps after the guy who invented a lathe-turning machine to engrave them. Sounds pretentious, but they still look nice:
With the ballpoint pen / knife collet holder in mind, I stripped the tool changes out of the Spirograph generator GCMC source code, set the “paper size” to a convenient 100 mm square, and tidied up the code a bit.
As with Spirograph patterns, changing the random number seed produces entirely different results. A collection differing in the last digit, previewed online:
Seed = 213478836:
Seed = 213478837:
Seed = 213478838:
Seed = 213478839:
They’re such unique snowflakes …
The Bash script now accepts a single parameter to force the PRNG seed to a value you presumably want to plot again, rather than just accept whatever the Gods of Cosmic Jest will pick for you.
The GCMC source code and Bash (or whatever) script feeding it as a GitHub Gist: