Cog & Petal · Engraver

Make a study

Choose fixed-ring and rolling-gear tooth counts, then set the pen distance. The pen follows a hypotrochoid as the inner gear rolls without slipping. Different ratios close after different numbers of turns. Tap the surface to center a new engraving, rotate it, then Engrave layer to keep the trace. Change gears and add more layers. This implements the circular gear subset of the source app, using its classic tooth-count sets. Save and compare engraved studies.

Original GPT-generated materials are bundled locally and used on the work surface. Source mechanism: https://github.com/ianmcman/spiro · MIT. An independent static adaptation; all editable program code and source notices are included.