This example renders a full-screen smiley face using React and D3.js version 7. The visualization is composed of three separate components: a yellow background circle with a black stroke, two black eye circles, and a mouth drawn with a D3 arc path. The code uses D3’s `arc()` API to generate the mouth’s curved shape, while the face elements are positioned relative to the center of the viewport. The SVG output is sized to match the browser window’s inner dimensions.