This example renders a full-screen smiley face as an SVG using React and D3. It draws a yellow circular face with a black stroke, two black eyes, and a mouth arc, all positioned relative to the window’s center. The visualization uses React function components with JSX to create SVG elements, and the D3 `arc` generator to compute the mouth’s path. All shapes are defined with fixed pixel offsets and radii, adapting to the browser viewport size.