# v4 · brush

The same line as v1, but painted rather than revealed: a felt tip stamps ink along the engine's strokes, so the marks are made in front of you instead of uncovered.

## What it does

- The skeleton and stroke order come from `marker.js` exactly as in v1 (his hand lifted from the photo). `brush.js` then runs a tip along each stroke at the local stroke width, stamping overlapping soft dabs with a slightly uneven deposit. The dabs jitter by a fraction of the width, so the edge is ragged the way felt on paper is; the tip dwells where a stroke starts and ends (more ink, a touch wider); the fast middle of a stroke runs a little thinner.
- Each dab also leaves a wet halo on a second layer that spreads wider than the stroke and dries away over about a second, so a fresh stroke looks darker and softer than one written two seconds ago: the soaking in, in motion.
- The sheet is v1's. The ink filter is set lighter here (the brush brings its own edge). `?text=your words` paints any line in Kalam Bold instead of the photo; `?t=`, reduced motion, grain and replay as in v1.

## Why

The owner asked for "realistic strokes as if a human hand is putting it to paper" and for the ink to look like it soaks in. Revealing (v1 to v3) keeps the exact final shape; painting (v4) gives the wet-to-dry life and a rougher edge at the cost of fidelity to the original marks. Seeing both side by side is the point.

## What it cannot do yet

- The dab is a stamp, not a fluid simulation: no feathering along fibres, no pooling that follows gravity, no colour shift as the ink dries.
- The finished line is close to the photo's but not identical (the brush follows the centreline and width, not the exact silhouette).