This example renders a simple cartoon face using D3.js v7 in an SVG container. A yellow circle forms the head, with two black circles for eyes and a D3 arc path creating a mouth that spans a quarter of a circle. The code uses D3 selections to append and style elements, and the `arc` generator from the `d3` module to compute the mouth’s path data. The SVG dimensions are read directly from the markup, and styles are applied via an external CSS file.