A grid of alternating horizontal and vertical rectangles creates a full-screen Sol LeWitt–style composition, masked by two large diamond shapes. The D3 code uses `select` and `range` to generate 100 rectangles in each orientation, applying SVG `mask` elements to reveal or hide strokes. It leverages D3’s `symbol` and `symbols` APIs to draw the diamond masks, with `translate` positioning them at the center. The rendering is SVG-based, sized to the window with `innerWidth` and `innerHeight`.