A black circle follows the mouse cursor across a yellow SVG canvas, responding instantly to every pointer movement. The visualization uses React's `useState` hook to track the current mouse coordinates and updates the circle's `cx` and `cy` attributes on each `mousemove` event. The root SVG element captures mouse movements via React's `onMouseMove` handler, and the circle is rendered with a fixed radius and black fill, creating a simple, direct interaction between the user and the graphic.