A yellow circle follows the mouse cursor within a fixed 960-by-500 SVG canvas. The React application tracks the pointer's client coordinates on the `svg` element and updates the circle's center position accordingly. The visualization uses React's `useState` and `onMouseMove` event handler, with `ReactDOM.render` to mount the component. The circle has a radius of 30 pixels and no fill color, rendering as a thin outline that trails the mouse movements across the blank white background.