This example reproduces Sol LeWitt’s geometric wall drawing using D3.js. It renders a grid of thin horizontal and vertical SVG rectangles across the full browser window, with each line colored by default. Two circular masks reveal the lines: the first shows a white circle over a black background, while the second inverts the effect, hiding the circle and showing the surrounding lines. The code uses `d3.select`, `d3.range`, and `selection.join` to bind data and create the rectangles.