This example shows a stylized smiley face built entirely with D3.js v5, featuring a yellow circle head, two eyes, and an animated mouth. The eyebrows move up and down repeatedly through chained `transition().duration()` calls on a group element. The code uses D3’s `select`, `arc`, and `attr` methods to construct SVG shapes, with the mouth defined by an arc generator using inner and outer radii and angle parameters. No external data source is involved; the visualization is purely generated from hardcoded dimensions and positions.