This example renders a yellow smiley face that fills the browser window using React components for the SVG elements and D3’s `arc()` generator to create the mouth. The face is centered with the `transform` attribute, while circles define the head and eyes, and a path receives the generated mouth arc. The code sets the circle and stroke dimensions based on the viewport height and width, with the mouth arc spanning from 90° to 270° using an inner and outer radius. The smiley face is drawn entirely in SVG, with no external data source.