This example demonstrates fundamental DOM manipulation with D3.js by building an animated smiley face. The face consists of SVG shapes—a green circle head, two eyes, eyebrows, and a mouth created with the `d3.arc` path generator. The code uses `d3.select` and `d3.append` to construct the elements, and `transition` with a 2000-millisecond duration to make the eyebrows move up and down repeatedly. The rendering approach relies on D3 v5’s selection and transition methods on SVG elements, with the face centered using an SVG `transform` translate.