Let's make a face with D3.js!
A smiley face rendered as SVG shapes uses green for the head, yellow strokes, and animated eyebrows that move up and down. The example demonstrates fundamental DOM manipulation with D3.js v5, building the face from circles, rectangles, and an arc-generated mouth while applying transitions to shift the eyebrow group. Code uses `d3.select`, `attr`, `transition`, and the `arc` generator, with a blue background set on the SVG.