This example shows a smiley face built entirely with D3.js that animates its eyebrows up and down. It demonstrates fundamental DOM manipulation by constructing SVG shapes—circles for the eyes, rectangles for the eyebrows, and an arc-generated path for the mouth—all centered within an SVG canvas. The animation uses D3’s `transition()` method to move the eyebrow group between two vertical positions over two-second intervals. The code relies on D3 v5’s `select`, `arc`, and `transition` APIs to create the static face and its looping eyebrow motion.