A moving circle follows the mouse cursor across an SVG canvas, with its position updating in real time as the pointer moves. The example uses React state management with the `useState` and `useCallback` hooks to track cursor coordinates, and renders the circle via SVG elements in a React component. Mouse move events trigger updates to the circle's center position, initialized to the middle of a 960×500 viewport. The visualization demonstrates a simple interactive pattern using React's declarative rendering and event handling.