Let's make a face with D3.js!
This example shows a yellow smiley face rendered in SVG, with its eyebrows moving up and down in a looping animation. The face is built entirely through D3.js v5 selections, using `append` to create circle, rectangle, and path elements, and `arc()` to generate the mouth shape. Eye spacing, eyebrow dimensions, and positions are defined as constants, while the eyebrow motion is driven by chained `transition().duration()` calls that shift the group’s `transform` attribute. The code runs in a standalone HTML page with a 960x500 SVG canvas.