This example shows a simple animated face built with SVG, featuring a yellow circle head, two eyes, and a mouth drawn as an arc. The eyebrows rise and fall repeatedly using D3 transitions. The rendering is done through D3 selections and the `arc` generator from D3, with the SVG elements styled via CSS attributes in the markup. The face is centered by translating a group element based on the SVG’s width and height, and animation is driven by chained `transition().duration()` calls that toggle the eyebrow group’s vertical position.