A circular SVG element follows the cursor as it moves across a 960x500 viewport. The visualization uses React's `useState` hook to track the mouse position via the `onMouseMove` event, updating the circle's `cx` and `cy` attributes in real time. The D3.js library is loaded but not used in the core interaction; the rendering relies entirely on React's declarative SVG output. This demonstrates a simple, direct mapping between pointer coordinates and a graphic element's position.