This example shows a smiley face drawn with basic SVG shapes whose eyebrows animate up and down. The face is built using D3 v7 selections to append a circle, eyes, rectangular eyebrows, and a mouth arc to an SVG element. The animation runs via chained `transition().duration()` calls on the eyebrow container's `transform` attribute, moving it between two vertical positions. The mouth is generated with a D3 `arc` generator, and all elements are centered within a 960×500 SVG canvas.