This example demonstrates how D3 SVG masks can create geometric patterns from overlapping rectangular bands. Two sets of perpendicular stripes, each consisting of 100 horizontal and vertical rects, are filtered through circular mask shapes generated with the `symbol` API. The first mask uses a filled star symbol to hide the horizontal lines, while the second, inverted mask reveals the vertical lines through the same symbol shape. The code uses `d3.select`, `d3.range`, and `d3.symbols` with the `join` pattern to render the full-screen SVG grid.