A smiling face rendered in SVG uses D3 v5 to construct circles, rectangles, and an arc-based mouth. Static yellow and black shapes form the head and eyes, while CSS transitions animate the eyebrows upward and downward over two-second intervals. The code directly manipulates SVG attributes such as `cx`, `r`, and `d` with an `arc` generator, and uses `transition.attr` to shift eyebrow positions.