A circle follows the mouse cursor across a blank SVG canvas. The visualization uses React state to track the cursor's coordinates and updates the circle's position on every mouse move event. It renders via SVG, with React's `useState` hook storing the x and y position and `useCallback` handling the move event listener. The circle is drawn with a fixed radius of 30 pixels, and the mouse position is initialized to the center of the 960 by 500 pixel viewport.