This example demonstrates how to build a simple smiley face in an SVG canvas using D3.js v5. It shows fundamental DOM manipulation by appending circles for the face and eyes, positioning them with attributes like `cx` and `cy`. The code uses `d3.select` to target the SVG element and `append` to create shapes, while also setting styles like fill colors. The face is static, with no interactive or animated elements, and the data is hardcoded rather than loaded from an external source.