Smiley Face Part IV
This example renders a classic smiley face using React and D3’s `arc` generator, which creates the mouth path. The face consists of a yellow SVG circle with a black stroke, two smaller circles for eyes, and a curved arc for the mouth, all centered on the screen. The code defines shapes with D3’s `arc()` and uses React components to structure the SVG elements, with hardcoded dimensions for the face features.