A grid of smiling faces is rendered, each composed of a yellow circle, two eyes, and a curved mouth. The React application maps over an array created with `d3.range` to generate multiple `FullFace` components. Each face uses randomized `eyeRadius` and `mouthWidth` values to vary appearance. Rendering is done through React with SVG primitives, while the smile path is built using the `d3.arc` generator to create an SVG path element. The faces are placed within a fixed 150 by 150 pixel viewport, centered on a common origin.