This example renders a geometric pattern of red vertical and black horizontal bars overlaid on a full-screen SVG. A circular white mask, created with the SVG `mask` element, reveals a clean circular window centered in the viewport, clipping the grid-like arrangement of rectangles. The code builds the visualization entirely with raw JavaScript and SVG APIs, setting attributes like `width`, `height`, `x`, `y`, and `fill` on each `rect`. No external libraries or data sources are used; the composition relies purely on procedural generation and CSS styling for typography.