A React-rendered SVG smiley face demonstrates basic D3 shape generation. The component uses `d3.arc` to create a mouth path with inner and outer radii and fixed start/end angles, while plain SVG `<circle>` elements position two eyes via negative and positive x-offsets from the center. The face is drawn inside a `<g>` transform that centers the artwork in a 960×500 viewport. The yellow circle has a black stroke, and the mouth is rendered as a half-circle arc, with all geometry computed from constant dimensions rather than data.