This example renders a yellow smiley face using React and D3 in an SVG. The face is centered with two eyes and a semicircular mouth, all drawn with basic geometric shapes and an arc generator. The code uses React 16.9 for component structure, ReactDOM for mounting, and the `arc()` function from D3 v5 to create the mouth path. The face is built with explicit pixel offsets and radius values, and the background circle is positioned using a translation transform.