This example visualizes a single black-outlined circle that follows the user’s mouse cursor across an SVG canvas. It shows an interactive direct-manipulation effect where the circle’s center repositions in real time to the pointer’s coordinates. The application is built with React using the `useState` and `useCallback` hooks to manage and update the cursor position. It renders a fixed 960x500 SVG element, and the `onMouseMove` event handler updates the circle’s `cx` and `cy` attributes based on the client coordinates.