This example shows a classic yellow smiley face with two eyes and a curved mouth, centered in an SVG canvas. Built with React for the component structure and D3’s `arc()` generator for the mouth path, the face uses circles for the background and eyes, with stroke widths defining the outline. The code defines a reusable `BackgroundCircle` component and renders the smiley by translating the coordinate system to the canvas center. The mouth is derived from an arc with explicit inner and outer radii and start/end angles, while D3 v5 is loaded via CDN alongside React 16.9.