house hand

The studio had a published style guide it loved and no hand that could draw in it. So the guide was read front to back and turned into twenty-one katas, about four to a belt, each with pass conditions written as things a reviewer could see. Every drawing on this page comes out of one Python file, house.py, which grew a function per belt: head, bean, tubes, hands, feet, garments, shadows, FX, and finally figure().

Two graders, and neither of them draws. svg_lint.py checks the mechanical rules on the SVG itself: one line weight, round caps and joins, palette colours only, no gradients or filters. Cloudflare's Clef model looks at the rendered picture and answers each rule as a probability. A sheet clears its kata at 1.8 out of 3 with no single check under 0.4. When a sheet stalled, the move was to ask the grader one claim at a time and fix whichever came back weakest, never to argue with the number.

The plates replay their own making. drawon.py traces every ink line at one steady pen speed, lets each shape fill with paper as it closes, then floods in the flat colours, the shadows and the effects. house.py marks the parts of each character as it draws them, so the replay goes the way an artist works: head first, feet last.

Four katas on single forms: the inflated cube, the smooth bean, tube discipline, reduce-by-half. This is where the lint grader was written: constant stroke width, round caps and joins, palette-only fills, no gradients or filters. Every later sheet has to pass it before a reviewer ever sees it.

The first lesson was cheap and permanent: the producer never grades its own work. The lint is deterministic; the visual judgement goes to a separate model.

The head is an oblong, not an egg: 1.2× taller than wide, flattened top and bottom. Eyes sit on the upper third, the mouth just below them. Kata 8 (the turnaround) took seven attempts; the breakthrough came from asking the grader one claim at a time — closed-lobe ears and a compressed far eye lifted it from 1.77 to 1.80.

Beans for torsos, tubes for limbs, and the two house rules the creative director set over the field guide: hands are three fingers plus a thumb (thumb 1.15×, not oversized), feet have four toes. Kata 9 needed the bean on the hip line and shoulders at 0.72× before it cleared.

Every opening is an ellipse with a lip; sleeves and trouser legs are 1.6–1.7× the limb. Every shadow is a more saturated version of its base hue, one hard-edged strokeless shape per form. FX — steam, sparkles, liquid, fire — carry no outline at all. The lint learned the saturated-shadow rule here (hue ±5°, saturation up, value down by at most 0.12).

The full-figure taste test. One library call, figure(), draws an on-model character from a view, a lean, arm and leg targets, hands, props and accessories. Kata 17 cleared once the sitting pose actually sat (hips at bench height); kata 18 cleared once the figures were drawn big enough for the grader to see cuffs and shadows at all — a rule the dojo now keeps: nothing under about 70px of head height on a graded sheet.

Depth without blur: overlap, scale and value only. The dark-key inversion swaps the shadow family in as the base and lights the scene with a strokeless halo. The twelve-frame loop exposed a real bug — figure() had a fixed ink width, so a half-scale figure drew with double-weight line — and taught the reviewer-facing trick of putting the seam on the sheet: frames 1 and 2 repeated, ghosted, after 12.

With the hand locked in, the real work: the phly.cloud mascot rebuilt as one closed silhouette with wings, cap, goggles and scarf (2.00 first time); the old mug scene redrawn with figure(); and the maths.teahub.xyz title card remade as a frame-by-frame animation from the same drawing library.

Two of those three never cleared the tangent check (0.36 against a 0.4 gate). The probe named the same thing every time: a figure or object resting on a horizontal set line. That's the rule the next version of the dojo gets — break the line with a clear overlap, or lift the thing off it.

Two new cast members, each with a card of her own: Bunny (kata 23) — long lilac ears, the right one flopping, a pink dress with puff sleeves and a cotton tail — and Unicorn (kata 24) — a gold spiral horn, pony ears, a lavender mane with one pink streak, white hoof boots. The library grew a little for each: hooks to draw parts behind, between and over the body, a palm that stays wrist-wide on big hands, and opt-in fixes for small figures, where the constant 10px line closes cuffs, soles and collars up into solid ink.

Bunny cleared at 1.81. Unicorn plateaued at 1.65 over seven grades and is committed ungated, with her scores. Then the two of them got a scene. The first version held hands, and every clasp — fingers under a fist, one fist hiding both hands — came back as the worst tangent on the page; a high five with a clear gap passed every check.

Posing them in the rig showed what the sheets hid: arms that grew from under the chin, a three-quarter view that put the far shoulder over the chest so they looked hunched, and a skirt drawn as if from below, with the legs behind its opening. Redrawn with the shoulders below the chin, each limb layered whole and the skirt seen from a little above, Bunny held at 1.81, Unicorn rose to 1.70, and the dance kept every check above 0.4.