A React-built smiley face renders as a pink circle with blue strokes, containing two dark eyes and a curved mouth. The visualization is constructed by splitting components into separate ES6 modules: `BackgroundCircle`, `Eyes`, and `Mouth`. The mouth uses `d3.arc` to generate an SVG path with specified inner and outer radii and angles. React Fragments in `Eyes` group multiple circles without extra DOM nodes. The app is drawn into an SVG canvas with a centered `<g>` transform.