A smiley face drawn with SVG shapes animates its eyebrows in a looping motion. The example demonstrates basic DOM manipulation and transitions in D3.js v5, using `d3.select` to append circles, rectangles, and an arc-generated path for the mouth. Eyebrow movement is driven by chained `transition().duration()` calls that shift the group's `transform` attribute up and down. The face is centered via an SVG group with translated coordinates, and all styling is handled through inline attributes and a linked stylesheet.