This example draws a smiley face using React and D3 version 5. The face consists of a yellow circle for the head, two black circles for the eyes, and a mouth rendered as an arc path. The code defines the head, eye, and mouth dimensions as constants, then uses React to create SVG elements and the D3 `arc` generator to compute the mouth’s path. The `stroke-width` attribute is set via JSX, and the entire group is centered using a transform translation. The visualization is rendered into the DOM via `ReactDOM.render`.