This example builds a smiley face using React components and D3’s arc generator. It renders an SVG containing a yellow circular head, two black eyes, and a curved mouth. The face is assembled from separate React components (`Head`, `Eyes`, `Mouth`, `FaceContainer`) that receive positional and sizing props. D3 v5 powers the mouth shape via the `arc()` API, while React 16.9 manages stateful rendering and DOM output. The result is a static, centered smiley face on a 960×500 canvas.