A React component tracks the mouse position and renders a single circle that follows it across an SVG canvas. The app uses React hooks (`useState` and `useCallback`) to store and update the mouse coordinates, which are passed directly to the circle’s `cx` and `cy` attributes. The circle is redrawn on every `mousemove` event, with its radius fixed at 30 pixels. The example demonstrates a basic interactive visualization built with React 16.9 and SVG rendering, without any additional data source.