This example shows a smiley face drawn with SVG circles and a D3 arc path. The face is centered within an 960 by 500 viewport, using a yellow circle with a black stroke, two smaller circles for eyes, and a D3 `arc` generator for the mouth. The code uses React to render the SVG elements, with D3's `arc` API to define the mouth's inner radius, outer radius, and angular range. All positioning is calculated relative to the center using constants for eye offset and radius.