Simon Willison asked Claude Opus 5.5 to build an interactive artifact that takes a photograph and rapidly paints a version of it using a canvas element and a simulated paintbrush. The request was simple but required the model to generate functional code in real time, specifically targeting a few-second generation window. This follows Willisons previous experiment where he got Claude Fable to simulate watercolor illustrations using P5.js.
The practical value lies in demonstrating how large language models can act as direct code generators for creative tools rather than just text assistants. It shows that users can bypass traditional development workflows to instantly prototype visual effects. The result is a functional web page that runs locally in a browser without needing external servers or complex setups.
* The output runs entirely within the browser using standard canvas APIs.
* Generation speed targets completion within a few seconds of interaction.
* This builds on earlier work simulating watercolor styles with P5.js.
