This example demonstrates mouse tracking by rendering a single circle that follows the cursor’s position across a 960×500 SVG canvas. The visualization, built with React and SVG, uses a `useState` hook to store the pointer coordinates, which are updated on every mouse movement via an `onMouseMove` event handler. The circle’s center is then re-rendered at the new `clientX` and `clientY` values, creating a direct, real-time interaction. The code relies on React’s state management and SVG’s declarative circle elements, with no external data source or processing.