A frame chopped into rectangles of different sizes, like a Mondrian or a newspaper layout.
The splitting has no plan behind it and nothing is stored. Every pixel works out its own rectangle from scratch, independently, and they all agree. It starts by considering the whole frame, then flips a weighted coin to decide whether to split it. If it splits, the pixel notices which half it landed in, keeps that half, and asks again. Up to six rounds later it knows exactly which rectangle it belongs to. Because the coin flip depends only on the rectangle's own position, every pixel inside a given rectangle flips the same coin and gets the same answer, and a consistent layout appears with no pixel ever consulting another.
density is the weighting on that coin, depth sets how many rounds. fill puts a shape inside each cell, and outline draws the divisions. Splits that would leave a very thin sliver are refused.