A yellow smiley face is drawn in SVG using React components for the background circle, two eyes, and a mouth. The face is centered within a 960-by-500 viewport, with the mouth generated by d3’s `arc` path using a half-circle start and end angle. React renders each facial feature as a circle or path element, and the code uses React 16.9 and d3 v5 to compose the visualization declaratively.