A smiley face drawn with SVG shapes animates its eyebrows, moving them up and down. The example demonstrates basic D3.js DOM manipulation by selecting the SVG element, appending groups, and building the face from circles, rectangles, and an arc path. The code uses `d3.select`, `d3.arc`, and chained `transition().duration()` methods to create the two-second eyebrow animation loop, with dimensions defined via attributes on the root SVG.