This example demonstrates a simple grid of blue squares rendered inside an SVG element. The visualization begins with a single static rectangle defined in the markup, then uses the D3.js `select` and `attr` APIs to programmatically append a looping series of additional rectangles, creating a dense 50-pixel grid pattern across the canvas. The underlying data is generated algorithmically rather than sourced from a dataset. The final result is an abstract, low-level exercise in shape composition, with the SVG output styled by a minimal external CSS file.