Fork of Let's Make a Face Part I
This example shows a simple smiley face built with SVG primitives in a React component, using D3’s `arc` generator to create a full circular mouth. The face consists of a yellow outer circle with a black stroke, two black eye circles positioned symmetrically, and the mouth path rendered below the eyes. The code explicitly sets width, height, center coordinates, and offsets for the eyes, demonstrating how fixed viewport dimensions and spacing constants drive the layout. It uses React 16.9 and D3 v7, with the SVG rendered directly into the DOM.