Two intersecting sets of thin SVG rectangles form a dense horizontal-and-vertical grid across the full browser window. A circular mask reveals only a central disk of this pattern, creating a moiré-like focal point against a plain background. The visualization is built with D3 v6, using `select`, `range`, and `data` joins to generate one hundred rectangles in each direction. The second mask inverts its fill to reverse the visible region, all rendered dynamically to the viewport's dimensions via `window.innerWidth` and `innerHeight`.