Let's make a face with D3.js!
A smiley face rendered in SVG demonstrates fundamental D3.js DOM manipulation. The face uses D3 selections to append a yellow circle, eyes, and a mouth via the `arc()` shape generator. With `transition().duration()`, the eyebrows animate upward and back, moving a group containing two rectangles. The code imports `select` and `arc` from the d3 module, targeting an SVG element sized through its attributes. Data is hardcoded as numeric constants for geometry, with no external dataset.