A single gray circle follows the mouse cursor across an SVG canvas. The circle’s position updates in real time based on the mouse’s client coordinates, mapped directly to SVG `cx` and `cy` attributes. Built with React hooks (`useState`, `useCallback`) and rendered via `ReactDOM`, the app listens to the SVG’s `onMouseMove` event, updating the circle’s location on every movement. No data source is used; the visualization simply demonstrates interactive pointer tracking with React and SVG.