This example demonstrates fundamental DOM manipulation with D3.js by building a smiley face with animated eyebrows. A yellow circle forms the head, with two eyes and a mouth drawn using an arc path. The eyebrows—rendered as rectangles—move up and down through a chained `transition().duration(2000)` sequence, shifting the transform attribute over time. The code uses D3 v5 selection methods like `append` and `attr`, plus the `arc` generator from the `d3` module, all rendered as SVG elements.