This example reproduces a Sol LeWitt wall drawing using D3.js and SVG rendering. It displays a grid of horizontal and vertical bars that intersect, with circular masks applied to create a rounded viewing window in the center of the canvas. The code uses D3’s `select`, `range`, and `join` APIs to generate the rect elements, and constructs two SVG masks—one with a white circle on black and another with a black circle on white—to reveal and conceal portions of the bars. The visualization fills the entire browser window, with the bars spaced at 20-pixel intervals.