This example draws a yellow smiley face centered on a full-screen SVG. The face uses a circle for the head, two offset circles for the eyes, and a mouth path generated with a d3.arc that creates an open smile. React renders the SVG elements, while D3 v5 provides the arc geometry, with the viewport dimensions determined by window.innerWidth and window.innerHeight. The face is positioned using a translate transformation, and stroke widths and radii are defined as constants.