Scatter some seeds; now colour every point of the plane by WHICH seed is closest. The plane shatters into cells — the Voronoi diagram — the same pattern you see in giraffe coats, cracked mud, soap foam, and cell tissue. It answers ‘whose territory is this?’ and it’s everywhere nature divides space. Slide the seed count.
A Voronoi diagram partitions the plane into cells, one per seed, where every point belongs to the cell of its NEAREST seed (Euclidean distance). Cell boundaries are equidistant between two seeds; three meet at circumcentres. It models territory, crystal grains, foam, and cellular tissue, and its dual is the Delaunay triangulation. A fail-loud self-check throws unless a test point is assigned to the argmin-distance seed. ◆ real computational geometry, node-verified.
The cells are rendered by sampling a grid (not exact polygon boundaries), so edges are pixel-approximate; the nearest-seed ASSIGNMENT rule is exact. Seed positions are procedurally generated for the demo.