A yellow smiley face is drawn in SVG using D3.js v5, with a circle for the head, two eyes, rectangular eyebrows, and an arc-based mouth generated with the `arc` helper. The eyebrows animate vertically via chained `transition().attr()` calls, moving down then returning over four seconds. The SVG dimensions are read directly from the markup, and the face is centered using a translated `<g>` group. The example demonstrates basic SVG shape creation and D3 transitions.