Put together a list of generator programs at:
EDIT: The links were:
- QR-Codes — QR Code and 2D Code Generator - Kerem Erkan
- Celtic knot work — Knotter download | SourceForge.net [Celtic cross help please]
- Lithophanes — http://3dp.rocks/lithophane/
- http://mandalacreator.com/
- Guilloche Pattern Extension - Inkspace the Inkscape Gallery | Inkscape
which includes:
c.f.,
(the author’s geargenerator site went commercial, so haven’t bothered to look at the license)