Show HN: I turned a sketch into a 3D-print pegboard for my kid with an AI agent

AI-generated 3D-printable pegboard toy from a hand-drawn sketch.

We have pegboards and plywood scraps all over the apartment. I wanted to make a tiny one for Oli, or maybe even hang one on our front door instead of a wreath so visitors would have something to play with.

I had already cut the scrap wood and drilled the first board when I sat down at the computer, ready to lose an hour or two in Fusion 360. Then I looked at the sketch on my desk, took a photo, pasted it into Codex, and added the only dimensions that mattered: the holes are 40 mm apart and the pegs are 8 mm wide.

About a minute later I had the first set of pieces. From there I just iterated a little: print, test, adjust, repeat, until the pegs fit snugly, the pieces felt good by hand, and the gears turned smoothly.

Everything in this repo stays as small Python generators instead of hand-edited meshes, which made those tweaks easy. The time I did not spend drawing every variant in CAD turned into time I could spend printing, testing, and playing with Oli instead.

The current set is a 40 mm system with seven play pieces, one tuned peg, four gears, and two printable boards.

This repo is intentionally easy to modify with coding agents. AGENTS.md has the current dimensions, folder layout, and the few rules needed to extend the set safely.

You can ask an agent to:

• build a bigger pegboard like 6x6
• make the pegs longer or shorter
• add new pieces for different peg combinations
• scale the whole system up or down
• generate tighter or looser fit-test variants

Technical specifications:

• Grid pitch: 40.0 mm
• Piece hole diameter: 8.45 mm
• Gear hole diameter: 8.45 mm
• Peg: 7.72 mm diameter, 40.0 mm long, 1.2 mm end roundover
• Printed board hole diameter: currently 8.30 mm, still being validated