A React application renders an interactive smiley face as an SVG circle that follows the mouse cursor across a 960-by-500 viewport. The component uses React hooks `useState` and `useCallback` to track pointer coordinates from the SVG's `onMouseMove` event, updating the circle's `cx` and `cy` attributes. The face's features—eyes and mouth—are static, while the orange head moves with the cursor. Rendering uses React DOM directly with SVG elements, with no external visualization library.