This example demonstrates fundamental DOM manipulation with D3.js by constructing a smiling face and animating its eyebrows. The code appends SVG shapes—circles for the face and eyes, rectangles for the eyebrows, and a path for the mouth—using D3’s `select` and `append` methods. The eyebrows move via chained `transition()` calls with a two-second duration, shifting their vertical position and then returning. The scene is rendered in an SVG canvas with a 960 by 500 coordinate space, centered through a transform.