Three overlapping circles create a Venn diagram by clipping full-canvas rectangles, with each circle pair and the central triple intersection filled with its own distinct color. The SVG rendering uses `d3.select` and `d3.append` to construct a `defs` element containing three `clipPath` circles, then applies those clip paths to colored rectangles. A white rectangle, clipped by all three circles, marks the center overlap, while complementary colors (yellow, cyan, magenta) fill the pairwise intersections on a dark background.