A smiling face follows the mouse cursor across an SVG canvas. The visualization uses React state to track pointer position via the `onMouseMove` event handler, updating a single circle's `cx` and `cy` coordinates. Rendered with React DOM and SVG elements on a 960×500 viewport, the circle moves in real time as the user moves the mouse, demonstrating reactive state-driven updates. The code uses React's `useState` and `useCallback` hooks to manage and optimize the position updates.