This example demonstrates fundamental D3.js DOM manipulation by creating an interactive smiley face with moving eyebrows. The face is rendered as SVG elements, and the eyebrows animate using D3’s `transition` and `attrTween` methods. The code leverages `d3.select` and `.append` to build the shape, while a YouTube video embedded in the README explains the process. The visualization uses `d3.v5` and is styled with external CSS, showing how D3 can handle simple, non-data-driven graphics.