This example demonstrates fundamental SVG shapes and attributes, showing how basic geometric elements are constructed and rendered in a web page. It uses the D3.js library, specifically the `d3.select` and `d3.append` APIs, to create and manipulate SVG elements dynamically. The visualization displays simple shapes such as rectangles, circles, and ellipses, with styling applied through SVG attributes like `fill` and `stroke`. The code is minimal and serves as an introductory reference for building data visualizations with SVG.