Smiley Face Part I
This example draws a yellow smiley face in SVG using React and D3. The face consists of a yellow circle with a black stroke, two black eye circles, and a mouth arc generated with D3’s `arc` function. The code defines the mouth’s inner and outer radii, start and end angles, and positions all elements relative to the SVG’s center coordinates. React renders the SVG markup, while D3 v7 provides the arc path generator for the mouth.