A PDF reader in which the figures move.
It reads any PDF. A figure that carries its own Python code gets a ▶ button: click it, and the figure plays as an animation, in place on the page.
Open one PDF or several; each gets a tab. Any PDF works. Those without live figures simply read as usual.
Figures that come with a recorded video start the moment you click them. A figure without one runs its Python code, which takes a few seconds the first time (the top right then says Python: ready).
Click ▶ on a figure, and click again to pause. Hover for ⟲, from the start, ■, the printed figure, and </>, its code.
← Back or Alt+← returns to where you were after a link or a tab switch, and finally here.
A live figure is a normal picture with its script inside the file. Other viewers show the picture, and clicking it opens the animation on the web.
Every figure's code can also run live: press Py on a figure. The reader then starts Python (Pyodide) in this window; the first time, that is a 30 MB download, after that it is ready in about 5 seconds.
Code runs only when you click a figure, in the browser's sandbox. It cannot touch your files, and nothing is uploaded.
For authors: a figure script defines fig and frame(k) and ends
with play(…); in LaTeX, \pyfig{name} places it and embeds the script.