A smiling face is constructed entirely from SVG shapes, with a yellow circular head, two dark eyes, eyebrows, and an arc-based mouth. The example demonstrates basic SVG composition and D3 selections, then animates the eyebrows by chaining `transition` calls to shift their vertical position. It uses D3 v5’s `select`, `arc`, and `attr` APIs to generate the mouth path and manage transform attributes. A centered `<g>` group positions all features, with fixed pixel constants controlling eye spacing and offsets.