D3 test
This example shows a simple yellow face built from SVG shapes, with eyes that blink through a repeating eyebrow animation and a smiling arc-shaped mouth. The code uses D3 v6 selections to append circles, rectangles, and a path to an SVG canvas, while the mouth is drawn with the `d3.arc` helper. A two-stage `transition` chain animates the eyebrows downward and back, demonstrating chained timing. The face is centered using an SVG transform, and static styling comes from the included stylesheet.