This example shows a smiley face rendered as a yellow circle with two black eyes and an open mouth, centered on the screen and sized to the browser window. The face is built entirely with React and SVG elements, using inline circle components for the head, eyes, and mouth. The code defines numeric constants for eye offset, eye radius, mouth width, and mouth radius, then applies them within JSX. React 16.9 renders the SVG markup directly into the DOM, with the face scaling to fill the viewport height and width.