Smiley Face Part 1
This example draws a yellow smiley face in an SVG using React and D3. The face consists of a large circle for the head, two smaller circles for eyes, and a D3 arc path for the mouth. The layout is centered on a 960 by 500 canvas, with fixed pixel offsets for the eyes and a mouth arc that covers the lower half. The code uses ReactDOM to render the SVG, and the D3 `arc` API with inner and outer radii to generate the mouth’s path.