This example demonstrates how to construct a simple smiling face using D3 version 7, with a yellow circular head, two black eyes positioned symmetrically, and a mouth drawn as an arc. The visualization renders entirely as SVG elements, using D3's `select` to target the root SVG and `append` to create circles for the face and eyes. The mouth path is generated with D3's `arc` function, specifying inner and outer radii and angular ranges in radians. The code also loads both D3 v7 and an older v5.6.0 version via script tags.