This example reproduces a Sol LeWitt-inspired geometric composition using D3.js v7. It layers two sets of thin rectangles—one horizontal, one vertical—across the full viewport, creating a grid-like pattern. Two SVG masks, each containing a D3 symbol (a cross), selectively reveal or hide portions of the rects by applying alternating black and white fills. The code uses `d3.range` to generate data, `d3.symbol` with `symbolCross`, and `d3.select` to append elements and masks.