This example shows a smiling face constructed from SVG primitives, centered within a 960 by 500 viewport. The face is built from a yellow circle for the head, two black circles for eyes, and a curved arc for the mouth. The code uses React to render the SVG elements and leverages the d3 `arc` function to generate the mouth path with specified inner and outer radii and angular extents. The drawing is positioned using SVG transformations, with the head’s stroke and radius explicitly defined.