This visualization recreates a Sol LeWitt–style grid of horizontal and vertical lines, overlaid with two masks that reveal symbolic shapes in contrasting areas. The example uses D3 v6 to generate 100 rectangular strips in each direction, then applies SVG masks via `d3.select` and `append('mask')`. Each mask uses D3 symbol generators (`d3.symbol` and `d3.symbols`) to draw numbered geometric icons—circles, crosses, diamonds, and squares—in black or white, creating a layered optical effect. The code directly manipulates SVG elements and relies on the `range`, `join`, and `attr` APIs to build the repeating structure.