A yellow smiley face with animated eyebrows demonstrates fundamental D3.js DOM manipulation. The face is built using SVG circles for the head and eyes, rectangles for the brows, and a `d3.arc` path for the mouth. The eyebrows move up and down repeatedly via chained `transition().duration()` calls that update the group's `transform` attribute. The example uses D3 v5 with selection methods like `append` and `attr` to construct and style elements within a 960×500 SVG canvas.