A React-driven SVG smiley face follows the mouse cursor across the full browser window. The application tracks pointer coordinates via React's `useState` and `useCallback` hooks, updating a single circle's `cx` and `cy` attributes on every mousemove event. It renders through `ReactDOM.render` into a root div, using the production builds of React 16.9 and ReactDOM. The visualization demonstrates real-time, state-based SVG interaction with no external data source.