A smiley face composed of SVG shapes animates its eyebrows in a looping sequence. The code builds the face using D3 selections, appending circles for the head and eyes, rectangles for brows, and a path from `d3.arc` for the mouth. Eyebrow movement is driven by chained `transition().duration(2000)` calls that shift the group’s `transform` attribute between two positions. The example demonstrates fundamental DOM manipulation and animation with D3 v5.