Three circles of different colors and sizes on a blank SVG canvas demonstrate the basics of SVG markup. The example shows how to draw and position shapes directly in HTML without any JavaScript interaction. The page uses D3 version 6 and includes inline SVG elements: two red circles and one black circle, each with explicit `cx`, `cy`, and `r` attributes. The accompanying `index.js` imports the `select` function from D3 and writes text to the page body.