This example draws a smiley face using React and D3, rendering SVG shapes inside a 960x500 viewport. It shows a yellow circle with black stroke for the head, two filled eyes, and a curved mouth generated from an arc path. The code uses React’s `ReactDOM.render` to mount the component and D3’s `arc()` API to compute the mouth’s path geometry based on specified angles and radii. All positioning relies on fixed numeric constants for offsets and dimensions, with D3 v7 loaded via CDN.