A smiling face is drawn with yellow circular head, black outline, two black eyes, and a curved mouth, rendered as an SVG in a React application. The face is centered within a 960×500 viewport, with the head radius calculated from the window height minus stroke width. The mouth uses D3's `arc` generator with specified inner and outer radii and angles, while circles are drawn as React SVG elements. D3 v6 provides the arc function within a React functional component, with all geometry defined using fixed JavaScript constants.