Many Generation-X geeks like me have happy memories of creating weird and wonderful geometric drawings with a Spirograph set — a toy invented in the 1960s in its modern form.
It occurred to me that the Lissajous-like patterns that the Spirograph produced would work well as laser engraver line art. The Spirograph’s gears can be easily replaced with lines of code, calculating the position the “pen” would be at for a given angle of rotation.
Circles-in-circles can produce some surprisingly straight paths!
Engraving was done (for the spirograph designs) at 10mm/s and 50% power, on an Atomstack 40W laser. The algorithm has constants for the radii of the outer (fixed) and inner (moving) circles. The point radius (corresponding to which hole is used for the pen) is a variable, but is typically held fixed for a complete cycle of 2N*pi radians. (The large hexagon in the above image is a sequence with the same inner and outer radii, and 31 different point radii from -15mm to 15mm.
Here’s the GitHub. Have fun!
