Let' make a face with D3.js
This example shows a yellow smiley face built with D3.js v5 and React, rendered as animated SVG. The code uses D3 selections and the `arc` generator to draw the face, circles for eyes, and rectangles for eyebrows. A chained `transition().duration(2000)` animation moves the eyebrows up and down, while the mouth is an arc path. The face is centered using SVG transforms, with all shapes positioned relative to the viewport dimensions.