A yellow circle face with eyes, eyebrows, and a mouth is drawn in SVG, then the eyebrows animate upward and back down using chained `transition` calls in d3.v5. The face is centered in a 960x500 SVG, with features positioned via SVG transforms and an arc path for the mouth. The animation runs continuously in a loop, demonstrating how SVG shape attributes can be transitioned with D3’s `transition.attr` method.