Accretion
Accretion is a browser drawing toy that grows ropes out of pointed cells. I started with a shape I had drawn by hand: two curves down each side, with short tails at the tips. Codex wrote the code. I directed it by looking at the output and explaining what was wrong.
I wanted the irregularities to accumulate. A cell drawn a little too wide should change the proportions of the next cells. My description was "every mistake gets passed forward." Giving each cell a fresh random distortion lost that relationship.
The early versions were too uniform. They made tidy ribbons, but the cells looked stamped onto a path. Later versions distorted the shapes until I could barely recognize the original drawing. I kept asking for the pointed cell back.
Each cell uses four cubic Bezier segments. Neighbors reuse the same curve for a shared edge, so the outlines stay connected as the rope turns. New growth inherits the current proportions, including their unevenness, until a later change alters them again. The code bounds those proportions because enough inherited error can flatten a cell or stretch it into a different shape.
Rope width and cell length ease toward new values along each arc. The curvature eases too, so the rope can tighten into a coil or straighten gradually. As it swells, it can add cells across its width, up to twelve. Making a wider band this way preserves the narrow cells I started with.
Autoplay chooses its own course. Clicking gives the growing tip a target while the existing drawing stays in place. I can drag to pan or scroll to zoom, and keep turning the drawing speed up. In Creator mode, I trace a ribbon and edit its width and cell size along the path. I can also change which ribbon passes over another and undo an edit.
Dark paper is the default, and the app remembers a switch to light. The download menu has a separate SVG for pen plotters. The screen can hide an old line with an opaque fill, but a plotter needs the hidden section removed from the path itself. The export clips those crossings, removes duplicate shared strokes, and fits the drawing to an A4 page with 10 mm margins. I haven't run a physical plot yet.