This example demonstrates fundamental D3.js DOM manipulation by building a smiley face with a yellow head, black eyes, and an arc-shaped mouth. The face is centered using an SVG group with a translate transform, with eye positions defined by fixed spacing offsets. The code uses D3 selections like `select` and `append`, plus the `d3.arc` API to generate the mouth path. All elements are rendered as static SVG shapes without animations or interactivity.