A circular shape tracks the user's cursor in real time, responding to every mouse movement across the full viewport. The visualization reacts immediately to input, with a fixed-radius circle redrawing its position wherever the pointer travels. Built with React, the app uses the `useState` hook to store the mouse coordinates and the `onMouseMove` event handler on the root `<svg>` element to capture position updates. The circle is rendered purely as an SVG element, with ReactDOM managing its placement, all within a full-window canvas that resets with the window size.