This example animates a simple cartoon face built from SVG shapes, with eyes, eyebrows, and a mouth arranged symmetrically. The face is constructed using D3 selections to append a circle for the head, circles for eyes, rectangles for eyebrows, and a path generated by the `arc` function for the mouth. The eyebrows independently animate upward and back down over two seconds using chained `transition` calls with `duration(2000)`. All elements are positioned relative to the viewport’s center via a transform on a group element.