This example demonstrates generating a grid of horizontal and vertical lines across the full browser window, masked by two circular cutouts. The alternating line orientations create a crosshatch pattern that appears only within the circular regions, leaving the rest of the canvas blank. The visualization uses D3's `select` and `range` functions to append SVG `rect` elements, with masks (`circle-mask` and `circle-mask-2`) defining the visible areas. The code highlights the declarative D3 API for data-driven element creation and SVG attribute manipulation.