A yellow circle follows the mouse cursor across a full-window SVG canvas. The circle’s position updates in real time to match the cursor’s coordinates, offset slightly down and right. The visualization uses React with the `useState` hook to track mouse movement and re-render the SVG circle on each event. The `onMouseMove` event handler captures `clientX` and `clientY` from the JavaScript `MouseEvent`, and the circle is drawn with a fixed radius of 30 pixels and a fill color of `#fcd947`.