This example renders a smiley face in SVG using React components and ES6 destructuring. It imports the `arc` function from d3.v7 to generate the mouth path via `mouthArc()`. The `BackgroundCircle` component receives a radius prop, while the main `App` component composes circles, a rectangle, and the arc path inside a translated group. React 18 renders the visualization into the `#root` element using `ReactDOM.render`.