A smiling yellow face drawn with SVG circles and arcs is centered in a 960x500 viewport. The face is assembled using D3 selections, with `circle` elements for the eyes and a `path` generated by the `d3.arc` function for the mouth. A group containing the rectangular eyebrows animates upward and downward via chained `transition` calls, each lasting two seconds. The example demonstrates importing `select` and `arc` from the D3 v7 library loaded via UNPKG.