Smiley Face Part III
This example shows a smiley face built with React and D3, rendered as an SVG graphic. The face consists of a gray circle head, two black eye circles, and a mouth drawn using a D3 arc path generator. React components structure the SVG elements, while D3’s `arc()` function defines the mouth shape with specific inner and outer radii and start and end angles. The code uses ReactDOM to render the component into the DOM, and SVG attributes control the positioning and styling of each shape.