A circle follows the mouse cursor across an SVG canvas, its position updating in real time to mirror pointer movement. The visualization demonstrates React state management and event handling, using `useState` to track the cursor's coordinates and `useCallback` to optimize the move handler. Rendering is done with React DOM into an SVG element, with the circle's center bound to the stored mouse position. The example uses React 16.9 and SVG, with the viewport sized at 960 by 500 pixels.