A simple smiling face built with React and D3, composed of a yellow circle, two black eyes, and an arc-based mouth. The example shows how D3’s `arc` generator creates the mouth path within a React SVG component hierarchy. All shapes are rendered as SVG elements via reusable React components (`BackCircle`, `Eyes`, `Mouth`, `Face`), with the face centered using SVG transforms. The code relies on `d3.arc` for the mouth, while static props control geometry, and ReactDOM mounts the visualization to the page.