This example shows a grid of horizontal and vertical bars covering the full screen, with two circular masks revealing the intersection of the bars. Each bar is a separate SVG `<rect>` element, generated using `d3.range` and `selectAll().join()`. The first mask uses a black background with a white circle to show the horizontal bars, while the second inverts the colors to show the vertical bars. The code relies on D3 v7’s `select` and `range` functions to construct the elements and masks dynamically.