This example renders a full-screen yellow smiley face using React and SVG. It positions two eye circles and a yellow head with a black stroke relative to the window’s center, using JSX elements and a `<g>` transform. The code leverages React 16.9 and ReactDOM, with dimensions and offsets defined as constants. The mouth is omitted, and the face scales to the viewport size via `window.innerWidth` and `window.innerHeight`.