This example shows a yellow smiley face drawn with SVG shapes, where the eyebrows repeatedly rise and lower in a looping two-second animation. The face is constructed using D3 selections to append a circle, two eye circles, two rectangular eyebrows, and a mouth path generated with the `arc` helper. The animation is implemented by chaining `transition().duration(2000)` calls on the eyebrows group, toggling its vertical transform. All geometry is positioned relative to the center of the SVG using a translated group.