This example uses D3 v7 to render a grid of 100 vertical and horizontal bar-shaped rectangles that intersect across the full viewport. A circular SVG mask, centered in the frame, reveals only the area inside its 200-pixel radius, while the surrounding bars remain hidden behind a white overlay rectangle. The code appends SVG elements via `select`, `append`, and `join`, and uses `range` to generate the data for each bar. The visualization demonstrates how SVG masks can selectively crop layered geometric compositions in real time.