A D3.js tutorial demonstrates basic DOM manipulation by constructing a yellow smiley face with animated eyebrows. The code appends SVG circles for eyes, rectangles for brows, and an arc-generated path for the mouth using `d3.arc`. A `transition` with a 2000-millisecond duration moves the eyebrows up and down repeatedly, showing chained state changes. The example relies on D3 v5 selections, `attr`, and `append` to build the face, with no external data source.