> replicate the elaborate machines that engrave currency
I think you may refer to a rose engine, which in operation is very close to a dimensional spirograph. A modern variant might be a core-xy open etch-a-sketch using those LCD writing tablets and a set of physical gears and pins that would control the stylus' motion, maybe powered by a folding handcrank like the Panic Playdate. It might even be a tool for teaching the Fourier series.
The watch manufacture Breguet (part of Swatch Group) still uses rose engines to make guilloché dials by hand, the effect is visually stunning.
Strangely enough, you can get a precious metal Breguet watch with a guilloché dial for less than the secondary market price of some steel Rolex sports watches.
Thank you for those links. Once upon a time I'd look at those watches and think "ok, fancy scratches" and now I think of them as an apex of math, machine and human touch. Reading about Breguet's work is amazing--all the things he invented and working through and escaping the French Revolution.
I think you may refer to a rose engine, which in operation is very close to a dimensional spirograph. A modern variant might be a core-xy open etch-a-sketch using those LCD writing tablets and a set of physical gears and pins that would control the stylus' motion, maybe powered by a folding handcrank like the Panic Playdate. It might even be a tool for teaching the Fourier series.
rose engine: https://www.youtube.com/watch?v=Gw3aCAQjC88
core-xy: https://corexy.com/
LCD writing tablet: https://www.mi.com/global/product/mi-lcd-writing-tablet/
Panic Playdate: https://en.wikipedia.org/wiki/Playdate_(console)
Teaching Fourier series: https://www.youtube.com/watch?v=qS4H6PEcCCA
Also, projects on Hackaday: https://hackaday.com/tag/spirograph/