A smiling face is rendered using D3.js, with its two rectangular eyebrows animating upward and then returning to their original position in a repeated cycle. The face is constructed from SVG shapes: a blue circle for the head, two circles for the eyes, and an arc for the mouth, all positioned within a centered group. The animation is achieved through chained `transition` calls on the eyebrow group, using D3's `.transition().duration()` and `.attr()` methods. The example demonstrates basic DOM manipulation and animation in D3 v5.