This example demonstrates how SVG masks can create a circular window onto layered geometric patterns. Using the native SVG DOM API, the code constructs fifty horizontal and fifty vertical rectangles, each with vibrant default colors, and applies two different masks to control their visibility. The first mask, built from a black rectangle and white circle, reveals only the horizontal bars inside the circle, while the second mask, with inverted colors, shows the vertical bars outside the circle’s edge. The result is a clean, mask-driven interplay of striped shapes across the full browser viewport.