A React-built smiley face uses yellow, red, and white SVG circles to render a face with eyes, nose, and a curved grin. The face is constructed from reusable components—BackgroundCircle, Eyes, and FaceContainer—that accept props for sizing and positioning. The grin uses D3's arc generator to draw a semi-circular path, while the overall SVG layout is centered via a translated group. The example demonstrates modular component composition and D3 integration within a React rendering pipeline.