They have to have rules for interacting, one set of rules setting out how each species responds to the rules in each other species: that's six sets of at least four rules, or (6 4) = 6 x 5 x 4 x 3 / 2 — oops, my earlier figure of 360 was incorrect, surprising no one caught that slip — or 180 rules of climate; that complex set of
unexamined and unknown rules practically makes the Stadium Wave impossible to sustain as a
model.