Turn Audio on, press ▶. 16 steps go clockwise from the top; outer ring kick, inner open hat. Pick where the pattern comes from:
Draw — tap segments to toggle hits, or start from a style template. Euclid — each ring spreads its hits as evenly as possible, E(k,16); select a ring and shift its phase for polyrhythms. L-system — a rewrite rule (A→AB, B→A) regrows the pattern every bar.
Same drums, same clock — only the pattern source changes: hand, formula, or grammar.