A completed cartoon smiley face is rendered as a static SVG using React components. The face consists of a yellow background circle, two black eyes, and a mouth drawn as an arc, all composited through custom React components like `BackgroundCircle`, `Eyes`, `Mouth`, and `FaceContainer`. The mouth shape is generated using the D3 `arc` API, while the overall layout is positioned within an SVG via a translated group. The example demonstrates reusable component composition and D3 integration within a React framework.