This example reproduces a Sol LeWitt piece using D3.js by generating a grid of horizontal and vertical lines. Two SVG masks, defined as "inner-mask" and "outer-mask", are applied to these lines to reveal or hide portions of the grid, creating a complex geometric pattern. The masks are constructed using D3's `symbol` and `symbols` APIs to draw paths that form the mask shapes. The code uses D3's `select`, `append`, `attr`, and `join` methods to build the SVG structure and apply data-driven attributes. The rendering is done entirely in SVG, scaling to the browser window size.