Smiley Face Part 1
This example renders a yellow smiley face in SVG using React, with a dark outline, two circular eyes, and an arc-based mouth. The face is centered by translating a group element to the middle of a 960×500 viewport. D3’s `arc` generator defines the mouth’s inner and outer radii and angular range, while React components compose the background circle and eyes. The background circle’s radius is set to the canvas half-height minus half the stroke width, positioning everything within the visible area.