This example shows a smiley face composed of three React components: a yellow background circle, two black eyes, and a curved mouth. The components accept parameters for radius, offsets, and stroke width, making the face customizable. The mouth is drawn using the `d3.arc()` API with inner and outer radii and specified start and end angles. The entire SVG is rendered with React 16.9 and D3 v7, positioned via a group transform at the center of the viewport.