A React app renders a yellow smiley face as an SVG graphic, using D3’s `d3.arc()` to create the mouth path. Hardcoded JSX circles serve as the face, eyes, and background, with stroke and fill properties set inline. The component structure separates the background circle into a reusable `BackgroundCircle` function, while D3 v6 and React 16.9 are loaded via external scripts. The code runs entirely in the browser without external data.