This example demonstrates a minimal integration of React and D3 by rendering a simple smiley face using SVG elements. The code sets up a React component that uses ReactDOM to mount an `App` component into the DOM, while loading React, ReactDOM, and D3 v5 from CDN sources. The visualization shows basic SVG shapes—circles for the face, eyes, and mouth—drawn in plain SVG markup within the React structure. The example serves as a starter template for combining React’s component-based approach with D3’s data-binding capabilities.