This example demonstrates a simple D3.js starter template that renders a grid of rectangles across the full window. The visualization uses nested loops to create SVG groups at regular intervals, with each group containing multiple rectangles positioned vertically. The code imports `select` and `range` from the d3.v7 library and uses data joins with `.join('rect')` to append elements. The page scales text to 13em and includes a YouTube tutorial link, while the JavaScript calculates grid margins based on window dimensions and sets the SVG size to fill the viewport.