A cheerful cartoon face built entirely with SVG shapes appears on a yellow circle, with two black eyes and an arc-based mouth. The example demonstrates how to use D3.js v5 functions like `select` and `arc` to append and position SVG elements. It reads the SVG’s width and height attributes to center the face, then applies a group transformation to place the mouth. The code also shows basic SVG styling through CSS, such as stroke and fill properties.