A React application renders a blank SVG canvas that follows the mouse cursor with a single black circle. The circle’s position updates on every mouse movement through React’s state management, using the `onMouseMove` event handler to capture `clientX` and `clientY` coordinates. The component re-renders to reposition the circle via the `setState` method, while the SVG viewport remains fixed at 960 by 500 pixels. This example demonstrates interactive state-driven updates in React with SVG elements.