# 731

How do these numbers relate to this pine cone? 1, 1, 2, 3, 5, 8, 13, 21....

Count the clockwise spirals

Count the counterclockwise spirals

Excellent. The series of numbers (1, 1, 2, 3, 5, 8, 13, 21, 34, 55...) is called the Fibonacci sequence. It is named after Leonardo of Pisa, who was known as Fibonacci. This sequence of numbers describes many things in nature, from the spiral of a snail shell to the arrangement of scales on a pine cone.

If you look at the top of a pine cone, you will notice that the scales are arranged so that there are spirals running clockwise, and spirals running counterclockwise. While different kinds of pine cones can have a different number of spirals, the number of clockwise and counterclockwise spirals will always be two adjacent numbers in the sequence. Looking at this cone, you can see that it has 13 clockwise spirals, and 8 counterclockwise spirals.

The next time you find a pine cone, try counting the spirals, and remember the Fibonacci sequence. It also works with the spirals of seeds in a Sunflower, the petals on an artichoke, and many other natural structures.

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