Two layered grids of thin rectangles sweep across the full screen, one horizontal and one vertical, creating a moiré-like interference pattern. Each grid is partially hidden by an SVG mask that reveals the shape of a large symbol—a star from the d3 symbol set—at the center. The code builds the visualization with D3 selections, joining data arrays to create 100 rects per grid, and defines reusable mask-rendering functions via `svg.call`. Rendering uses SVG elements within a React framework, with masks composed of a full-screen rect and a symbol path.