This example shows a smiley face built with React and D3, rendered as an SVG. The face consists of a yellow circle with a black stroke, two eye circles, and a mouth drawn using D3’s `arc` generator with specified inner and outer radii and angular ranges. React manages component structure and state, while D3 provides the `arc` function to compute the mouth path. The SVG coordinates are centered via a translated `<g>` element, with all shapes positioned relative to that origin.