This example creates a striped grid of horizontal and vertical rectangles, each masked so that the overlap reveals alternating symbol shapes. The visualization uses D3 v6’s `symbol` API to draw seven distinct shapes—circle, cross, diamond, square, star, triangle, and wye—as SVG paths inside two mask definitions. The masks are applied via the `mask` attribute to the rects, which are generated with `d3.range` and `join`. The page captures the full window dimensions, scaling the SVG and grid accordingly, and demonstrates a minimal React-free setup with D3 selections.