This example renders a grid of twenty yellow smiley faces, each composed of SVG circles and a d3.arc-generated mouth path, using React components for modular assembly. The `FaceContainer` component positions each face’s features (eyes, smile) relative to its width and height, while `index.js` maps over a `d3.range(20)` array to create the repeated faces. The app uses ReactDOM to mount the output into a root div, with styling that hides page margins and overflow. The D3 v6 `arc` API calculates the smile’s curved path.