The idea
This is a painting that nobody composes. There is a painter. It is a small program, sometimes a language model, and it knows how to do exactly one thing: make the next physical mark. A brush stroke. A drip. A flick of the wrist. A scrape back to the paper.
It is never shown a finished picture and never asked for one. Nobody tells it to be beautiful or meaningful. Each time someone holds the button, the painter considers what is already there and commits one more irreversible gesture. The painting is only the history of those gestures. Whatever it becomes, it becomes.
One canvas, shared
Everyone who visits paints on the same canvas. Your gestures land beside strangers'. Each visitor is given a painter's name, something like Cobalt Heron. Every mark goes into the provenance, like a conservation record: who made it and when.
Your name is tied to a key your browser keeps. If you copy the key, you can resume the same identity anywhere.
Whispering
You may whisper a request before a gesture, like "a faint teal smear across the top", and the painter will honor it in its own way. It still makes only one mark. It still doesn't plan.
Nothing is destroyed
Every gesture is stored as a small transaction, which is why the replay slider can rebuild the painting from its first mark, a time-lapse of its whole life. When a canvas is retired, or fills up and is sealed, it isn't deleted: it moves to the gallery of past paintings, complete and replayable, and a fresh canvas takes the easel.
Why the paint looks like paint
The marks are not clean vector lines. Wet strokes glaze and darken where they overlap, dry brushes skip, drips bead under gravity, the palette knife leaves a raised edge with a lit ridge, and a scrape genuinely scratches paint away. Older paintings grow dense and dark, the way real thin paint does. That is allowed. A canvas has a life.
Built as one small, self-contained thing. No accounts, and nothing tracked beyond your painter's key. Just the next mark.