Paint worklet

The code runs in a worklet — a stripped-down context with no DOM access that can run off the main thread — and gets a drawing context resembling canvas. The elegant part is how it connects to the rest of CSS: the worklet class declares which custom properties it reads, and the browser repaints automatically when any of them change, meaning the result can be animated and transitioned with ordinary CSS. The uses are patterns, dynamic borders, wavy edges and decorative shapes that would otherwise be an SVG file or a hand-maintained data URI. The technique works and is genuinely elegant, but has only ever been implemented in Chromium, which has kept it a curiosity rather than a tool.