Smiley Face Part IV
This example renders a classic smiley face as a scalable vector graphic using React components and D3’s `arc` generator. The yellow circular face, two eyes, and a curved mouth are drawn with SVG elements, with the mouth positioned using an arc path that spans a half-circle. D3 provides the arc geometry, while React manages the component structure and state-free rendering into the SVG container. The face is centered in a 960 by 500 viewport, with fixed offsets for the eyes and mouth radius, demonstrating a simple, declarative integration of D3 shapes with React’s virtual DOM.