Smiley Face
A yellow smiley face is rendered in an SVG using React components. The face consists of a yellow background circle with a black stroke, two black eyes positioned symmetrically, and a mouth drawn as an arc. The mouth uses `d3.arc()` with specified inner and outer radii and start/end angles to create a smile shape. Coordinates for the eyes and dimensions for the mouth are defined as constants, and the entire face is centered within the SVG viewport.