This example demonstrates how different SVG shapes—circles, rectangles, lines, and paths—can be styled and combined using D3’s square-root scale and CSS. It shows the same shapes in three group configurations: default styling, explicit fill and stroke attributes, and a group with shared fill/stroke properties. The `d3.scale.sqrt` function is defined but not applied. The SVG uses a `transform` scale, while CSS classes control stroke width, color, and line join/cap styles for the line and path elements.