This example shows a yellow smiley face built from SVG primitives—a background circle, two eye circles, and a mouth arc—centered on a 960-by-500 canvas. The face is composed entirely of React components, with the `BackgroundCircle` defined as a reusable component and the `App` component rendering the full SVG. The mouth’s crescent shape is generated using D3’s `arc` generator, which supplies the `d` path data. The code imports React, ReactDOM, and D3’s `arc`, and renders the result into a `#root` div, demonstrating how to combine React’s component model with D3’s geometric utilities for declarative, ES6-based visualization.