This fork of Mike Bostock’s D3.js face tutorial demonstrates basic SVG construction and animation by building a smiley face with moving eyebrows. The code selects an empty `svg` element and applies a red background via `svg.style`. It relies on vanilla D3 v5 methods, including `select` and likely `append` and `transition` to manipulate shapes, though only the initial selection is visible in the provided snippet. The example uses SVG markup inside a 960×500 viewport, with styles defined in a separate CSS file.