This would've been a lot less confusing if they'd used let radius = d * random(random(random())) instead of let radius = d * (1 - random(random(random())))

This would've been a lot less confusing if they'd used let radius = d * random(random(random())) instead of let radius = d * (1 - random(random(random()))) But, if so, probably so much less confusing that folks wouldn't be talking about it here, to be honest.