This example renders a yellow smiley face that fills the browser window using React and SVG. The face is built from three circles: a large yellow head with a black stroke, and two smaller black circles for eyes positioned symmetrically around the center. The code uses `window.innerWidth` and `window.innerHeight` to make the visualization responsive, and computes the head’s radius from the viewport height. React components define the SVG elements, with JSX attributes matching SVG properties like `stroke-width`.