This example demonstrates how SVG masks can create complex visual effects by combining shapes. A white rectangle covering half the canvas contains a black circle and a smaller white circle, which together punch holes in the mask. The page renders 100 horizontal strips, each with a mask applied, creating an alternating pattern of visible and hidden regions. The code uses raw JavaScript to manipulate SVG elements directly, setting attributes like width, height, and fill on rectangles and circles within a masked group.