A smiley face follows the mouse cursor across the screen, rendered as a single SVG circle that moves in real time. The React component tracks pointer coordinates via the `onMouseMove` event handler, updating state with `useState` and `useCallback` to reposition the circle’s center. The visualization uses React DOM to render the SVG element directly to the page, with the circle’s radius fixed at 30 pixels. No external data sources are involved; the interaction is purely based on mouse position.