This example builds a smiling face in SVG using D3.js v5, with a yellow circle for the head, two eyes, and an arc-shaped mouth drawn via `d3.arc()`. The eyebrows are rectangles that animate up and down repeatedly using chained `transition().duration()` calls, creating a winking or surprised effect. The entire face is centered by translating a group element to the middle of an 800×400 SVG canvas, with dimensions read from the SVG attributes and hard-coded offsets for facial features.