This example demonstrates a generative grid of horizontal and vertical striped bars rendered as an SVG, overlaid with circular mask effects that reveal or conceal portions of the pattern. The code uses D3 v3’s selection, selection, range, symbols, and symbol APIs, appending rectangles to an SVG canvas sized to the window. Two masks are created via the renderMask function, each with a path drawn from the symbol API’s circle shape, applying inverted fill logic to produce contrasting visibility. The visualization is purely procedural, with no external data source.