The visualization draws a grid of overlapping horizontal and vertical bars across the entire viewport. Two sets of 100 rectangles each are created using D3's selection and join operations, with dimensions tied to the window size. Masking via SVG circle masks creates a central circular window that reveals alternating black and white stripes. The code uses `d3.select`, `d3.range`, and chained SVG attribute setters within a React-free HTML page.