This example uses React 16.9 and SVG to render a full-window smiley face. The face is drawn with a yellow circle for the head, two black circles for eyes, and no mouth, centered based on the viewport dimensions. The code uses ReactDOM to mount the component and computes positions from `window.innerWidth` and `window.innerHeight`, with constants for eye offset, radius, and stroke width. The SVG elements are grouped and translated to the center of the screen.