This example demonstrates fundamental DOM manipulation with D3.js by building a yellow smiley face from SVG primitives, complete with eyes, eyebrows, and a mouth. The eyebrows animate up and down using chained `transition().duration()` calls, shifting the eyebrow group’s `transform` attribute over two seconds. The code uses `d3.select` and `d3.arc` from the D3 v7 library, setting positions via `attr` and leveraging SVG circles, rectangles, and a path for the arc-based mouth.