one rule: each cell looks at the three cells above it and follows a fixed table. that's the whole program. one lit seed cell at the top, run downward. rule 90 gave a clean sierpinski triangle; this is rule 30, and the same one seed blooms into something that looks like noise. no randomness, no tuning, no second rule. it's deterministic all the way down, and it's the reason wolfram used this rule as a random number generator.