A red circle follows the cursor inside an SVG canvas in this React-based interactive visualization. The example demonstrates a mouse-follower interaction using React's `useState` hook to track pointer coordinates and update the circle's `cx` and `cy` attributes in real time. The `App` component renders an SVG element with an `onMouseMove` event handler, which calls `setMousePosition` on each pointer movement. The circle’s position is bound to the stored mouse coordinates, creating a direct visual response. The code uses React 16.9.0, ReactDOM, and the SVG `circle` element, with the canvas sized at 960 by 500 pixels.