Eb had no idea what to say to this, at all. His world still didn’t have the Fibonacci sequence. He hadn’t the faintest idea what she was talking about.

“Huh!” he said, to prevent his moment of floundering from lengthening into obvious defeat: “There’s a plenty you could say about mating rabbits, but I wouldn’t dignify it by using the word ‘pattern’!”

“No,” said Flo. “I guess you might not. You and most other trolls and the overwhelming majority of human beings with you.

“But because Fibonacci paid attention to rabbits’ breeding patterns eight hundred years ago, seeing that a rabbit can mate from one moth old, he figured out that at the end of the first month, if the first pair of rabbits has sex, and produces more rabbits, then at the end of the second month, you have the original pair, plus a new pair –so two pairs, then at the end of the third month the first pair have produced a new pair, and the second pair are ready to mate, giving you three pairs – then by the end of the fourth month, the first pair has added a new pair, the second pair have their first set of babies, so there are now five pairs in total. And so on and on it grows, giving us what’s come to be called the Fibonacci series, where the next number in sequence is determined by adding together the two previous numbers – 0+1=1, 1+1=2, 1+2=3, 2+3=5, 3+5=8 and so on. But what’s so amazing is that this pattern turns out also to determine the number of spirals in flower seed-heads, um – not all of them but sunflowers and Echinacea among others. If you look carefully at the ripened seed-head, and count the number of spirals leading off to the left and the number leading off to the right, those numbers will be two subsequent numbers on a Fibonacci series. So I think it may be worth talking to rabbits after all don’t you? Seeing without the Fibonacci series we would never have had the golden ratio and phi!”

Eb swallowed. “No wonder your hair’s pink,” he said.