Case study — spec first, machine second

The Going Train

A clock blueprint I drew seven years ago. An AI ran it this year. Physics sent a bill. I paid it.

Artifact · hand-drawn movement, every tooth count true Test · the machine rebuilt it from the layer names alone Result · the original linework, running below The bill · a 4 cm pendulum + a 0.4° limp — both caught by math

The system

A clock is a spring that wants to explode — counted.

The drawing is the spec: named layers, true tooth counts, both lever poses drawn in. The machine measured it — jewels, spokes, ghost overlays — and set it running. Turn on the tick.

Time scale

True speed. The balance beats 2.5 times a second; the escape wheel ticks 24° per beat; the fourth wheel is your second hand. The center wheel takes an hour per turn and the barrel takes six — they're moving, you just can't prove it. That spread is the point.

Reduced motion is on, so the train is holding still — which, at this scale, is nearly honest: the center wheel takes an hour per revolution.

1 barrel revevery 6 hours→ ×6 → 6 centerminute hand→ ×8 → 48 thirdthe middleman→ ×7.5 → 360 fourthsecond hand→ ×10 → 3,600 escape15 teeth each→ ×15 → 54,000 beats9,000 / hour

The spec

Drawn to be checked, not admired.

No client, no deadline — I took a movement apart on paper to understand it. Every gear carries its true count; the ratios live in the layer names. Seven years later, an AI rebuilt the running train from the file alone. Nothing to guess. Everything to audit.

The bill

Run a drawing and you audit it.

Item one: my pendulum variant pairs a watch's 18,000 beats per hour with a bob that physics prices at 4 cm long — an oversight in my research, caught by the arithmetic. Item two: I drew the pallet jewels 54° apart where geometry wants 60°, so the second hand above limps ±0.4° on every tick. It stays. The drawing is the spec, and I don't launder my own numbers.

The fix

How a grandfather clock pays it: remove a wheel.

Drop the fourth wheel. A 30-tooth escape turns once per minute and carries the second hand itself; the beat slows to one per second; the pendulum becomes the 994 mm seconds pendulum. That's why longcase clocks are as tall as their owners — and why the balance-wheel version, at true wristwatch rate, needed no fix at all.

The full hand-drawn clock movement blueprint: dial and pointers, motion works, power source, wheel train, escapement, strike train, plus two assembled composite stacks, in white and gold linework on blueprint blue. — The sheet. **Six subsystems, exploded by job** — the whole movement, falsifiable.

The alternate escapement study: a recoil anchor and pendulum on the same 15-tooth escape wheel. — Exhibit for the bill: **the pendulum variant** — drawn as a sibling, priced by physics at 4 cm.

▸ Ledger. Human: the study, the drawing, every count — and this year, corrections made on canvas, where geometry belongs. AI: measured the drawing, ran it, computed the bill. Errors kept and labeled, because a spec you can catch is the whole point.