A smiling face drawn with SVG shapes animates its eyebrows up and down. The code uses d3.js v4 to construct the head, eyes, eyebrows, and mouth from circles, rectangles, and an `arc()` path, all centered via a transformed `<g>` element. Animated with `transition().attr()`, the eyebrows move vertically over two seconds, then return, demonstrating chained transitions in a React project.