These cards are scripted messages. Each one carries a <script> that runs in its own JavaScriptCore sandbox. It defines render() (state → HTML) and onAction(name, value), which is called when you click anything with a data-action. Every click updates the same bubble in place: tween() and animate() move numbers, sizes and colours at up to 60 fps, and transition('pop') or 'slide-left' lets the bubble animate natively when its content swaps. Right-click a card and pick Script Log… to see its console.