A simple SVG face built with React and D3 renders a yellow circle with two eyes and a mouth. The background circle uses the `BackgroundCircle` component, while the mouth is generated using `d3.arc` with specified inner and outer radii and angle ranges. Eye positions are set via SVG circle coordinates, and the entire group is centered using a translate transform. All shapes are drawn directly as SVG elements within a fixed 960×500 viewport.