A circle follows the mouse pointer across an SVG canvas in this interactive React example. The pointer's screen coordinates are captured by a mouse-move event handler and stored in component state, updating the circle's center position in real time. The visualization uses React's `useState` and `setMousePosition` for state management, ReactDOM for rendering, and renders output as SVG elements. The data is the live mouse position, with coordinates normalized to the 960×500 viewport, and the circle has a fixed radius of 30 pixels.