This example shows how to assemble a simple cartoon face from basic SVG shapes. D3 version 6 is used to select the SVG element, append circles for the head and eyes, and draw a mouth using the `d3.arc` shape generator. The face is centered within a 960×500 pixel viewport, with the mouth positioned via a translated group element. The code relies on standard D3 selection methods and the `arc()` generator to define the path for the mouth.