A full-screen SVG rendering creates a circular viewport into a dense field of 100 vertical black stripes, each 10 pixels wide and spaced 20 pixels apart. A mask with a white circle on a black background reveals the stripes only within that circle, while the rest of the canvas remains hidden. The code builds the SVG and mask elements using the raw DOM API, and it relies on D3 v7 only for the script import, with no D3-specific functions invoked.