A sad smiley face drawn entirely with SVG shapes demonstrates basic D3.js DOM manipulation and animation. The code uses `select` to target the SVG element and `append` to create a yellow circle, eyes, and rectangular eyebrows. A `transition().duration()` sequence moves the eyebrow group down and back, creating a repeated frowning motion. The mouth is generated using the `arc()` generator from D3's shape module with specified inner and outer radii and angle values.