A smiley face built with SVG and animation shows a yellow circle with two eyes, a grin, and rectangular eyebrows that repeatedly raise and lower. The face is centered in a 960 by 500 viewport, with features positioned via explicit coordinates in the D3 v7 selection and arc API. The eyebrows use chained `transition.attrTween` calls on the `eyeBrows` group to loop between two transforms, while the mouth is drawn with `d3.arc()` using inner and outer radii and angle offsets.