Smiley Face Part I
This example draws a yellow SVG smiley face with black outlines, consisting of a large circular head, two offset eye circles, and a full circular mouth created using D3’s `arc()` generator. The React component renders three `<circle>` elements and one `<path>` for the mouth, with dimensions computed from fixed width and height constants. The mouth arc uses inner and outer radii to produce a ring shape, while the eyes are positioned symmetrically around the center. All shapes appear centered within a 960×500 pixel viewport, with no additional data or interactivity.