The answer, it turns out, is 144 — and the formula used to get to that answer is what's now known as the Fibonacci sequence. Read more: 9 equations that changed the world "Liber Abaci" first ...

Flickr user eager licensed under CC BY-ND 2.0. More than that, this sequence of numbers can be found in several species of nature - from the snail to the sunflower, in its most classic examples ...