A yellow smiley face rendered with React and D3 v5. The code draws a large yellow circle for the face, two black circles for the eyes, and a D3 `arc()` path for the mouth. The SVG is constructed using React’s declarative JSX syntax, with D3 providing the mouth arc’s geometry via its `arc()` generator. All shapes are positioned relative to the center of the 500-pixel-tall viewport, with the face circle’s radius based on the height minus a stroke width.