This example renders a smiley face from reusable React components inside an SVG. It uses the D3 `arc` generator in the `Mouth` component to create a semi-circular path, while `BackgroundCircle` and `Eyes` draw simple circles with fixed offsets and radii. The `index.js` file sets coordinates for the center, eye spacing, and mouth dimensions, then passes them as props within a transformed `<g>` element. The visualization demonstrates component composition and parameterized drawing with D3 v7 and React, using only static SVG markup without interactivity or data loading.