A grid of 18 yellow smiley faces, each rendered as an SVG, demonstrates a React and D3 integration. The code uses `d3.range` to generate the array and `d3.arc` to create the mouth path, while each face’s eye size is randomly varied via `Math.random()`. The `FaceContainer` component, defined in `smiley.js`, combines a `BackgroundCircle` and positioned eye circles within a translated `<g>` element. This example shows how to build custom SVG components with React and D3’s shape generators.