This example builds a cheerful, animated smiley face using D3.js (v5) and SVG. It demonstrates core DOM manipulation and transitions by drawing a yellow head, eyes, eyebrows, and a mouth with the `d3.arc` path generator. The code sequentially applies a 2-second `transition` to shift the eyebrow group vertically, creating a bobbing motion. The face is centered and scaled relative to the SVG’s dimensions, with all shapes positioned using calculated offsets for eyes and brows.