This example displays a classic yellow smiley face with two eyes and a wide mouth, drawn using SVG circles and a path. The face is centered within a 960 by 500 pixel canvas, with all geometric properties (center, eye offsets, radius, and stroke width) defined as constants. The mouth is generated using the D3 arc generator, which creates a semicircular path through the `arc()` API. The visualization is built with React, where the `App` component returns an SVG element, and is rendered to the page via `ReactDOM.render`. The code uses D3 v5 and React 16.9.0.