Version two is in the repo because it failed: a micro cycloidal drive squeezed to a NEMA 17’s footprint, defeated by tolerances a 3D printer cannot hold. Version three works — 90mm across, ten outer pins, nine rotor lobes, 1:9. The real object here is the Fusion 360 script that draws the profile from pins, pitch radius and eccentricity, so you can generate a ratio the author never printed.