This example reproduces a Sol LeWitt art piece using D3.js, rendering a grid of horizontal and vertical SVG rectangles overlaid with two circular masks. The first mask creates a circular hole in the center of the horizontal lines, while the second mask reverses the effect, leaving a solid circle in the middle of the vertical lines. The code uses `d3.select`, `d3.range`, and the `.join()` method to construct the SVG elements, with masks defined via `append('mask')` and composed of `rect` and `circle` shapes.