This example shows how to build a simple cartoon face using SVG primitives in D3. It draws a yellow circle for the head, two black circles for eyes, and an arc-based path for a mouth, all positioned relative to the SVG’s width and height. The code uses `d3.select` to access the SVG element, `append` to create shapes, and the `d3.arc` generator to compute the mouth’s path with inner and outer radii and specified angles. The face is centered horizontally and vertically, with fixed offsets for the eyes and mouth placement.