The Fibonacci sequence is a series of numbers in which each number is the sum of the two that precede it. Starting at 0 and 1, the first 10 numbers of the sequence look like this: 0, 1, 1, 2, 3, 5 ...

This spruce cone displays a marked fibonacci number sequence. The sequence, thought up by 13th-century Italian mathematician Leonardo of Pisa, pen name Fibonacci, plays out in plants, from pine ...