A smiley face rendered in SVG with D3 v5 demonstrates fundamental DOM manipulation. The face consists of a yellow circle, two eyes, rectangular eyebrows, and an arc-based mouth created using `d3.arc()`. The eyebrows animate upward and back downward over four seconds via chained `transition().duration()` calls, shifting the eyebrow group's `translate` transform. The code uses `d3.select` to append elements, reads the SVG dimensions for centering, and positions features with explicit x/y offsets and eye spacing constants.