Smiley Face Part 1
A grid of randomized smiley faces is rendered as SVG in React. Each face uses a yellow circle with a black stroke, two eyes, and an arc-based mouth. The `d3.arc` API generates the mouth path, while `d3.range` creates 18 face instances with randomly varied dimensions for eyes, stroke width, and mouth radius. The `FaceContainer` component translates the coordinate system to center each face within its 160 by 160 pixel viewport.