This example renders a smiley face as a reusable React component, demonstrating how to integrate D3’s `arc` generator with SVG elements. The face is drawn using a yellow circle for the head, two small eyes, and a mouth path created by the `arc` function with specified inner and outer radii and angular extents. The code uses React’s declarative `JSX` syntax to define the SVG structure, while D3 v5 provides the geometric calculations for the mouth shape. The component is mounted into the DOM via `ReactDOM.render`, with dimensions and offsets defined by constants.