This example shows a smiling face built from basic SVG shapes, centered on a yellow circle with a black outline, two eyes, and a curved mouth. The face is rendered using React components that generate SVG elements, with the mouth created using D3’s `arc` generator to produce a path. The code uses React’s `ReactDOM.render` to mount the app, and D3 v5’s `arc` API to define the mouth’s inner and outer radii and angles. The background circle, eyes, and mouth are positioned relative to a central transform group.