A single circle follows the mouse cursor within an SVG canvas. The circle’s position is updated via React state, triggered by an `onMouseMove` handler that tracks `clientX` and `clientY` coordinates. The example uses React 16.9 with hooks (`useState`, `useCallback`) and renders the SVG element with the circle’s `cx` and `cy` attributes bound to the current mouse position. The visualization demonstrates a simple interactive pattern with minimal code, relying solely on React’s state management and SVG rendering.