This example uses React to render an SVG circle that follows the mouse pointer across a 960×500 canvas. The component tracks the mouse position with the `useState` hook and updates it on every `mousemove` event via `handleMouseMove`. The circle’s center coordinates are set directly from the event’s `clientX` and `clientY` values, producing a simple interactive follower. React 16.9 and ReactDOM are loaded from UMD builds, with the SVG output defined declaratively in JSX.