A React-driven SVG visualization displays a single circle that tracks the mouse cursor across a 960 by 500 canvas. The circle's position updates in real time through React's `useState` and event handling, with the `onMouseMove` callback capturing cursor coordinates. Built with React 16.9 and D3 v7, the rendering uses pure SVG elements, with the circle's center coordinates bound directly to the mouse position state. The visualization demonstrates a minimal interactive pattern, showing how React state management can drive SVG geometry updates without additional D3 layout or force simulation functions.