# Fibonacci Day

**Celebrated every year on November 23.**

The Fibonacci sequence sounds like an obscure nerd thing.

Which in some sense it is.

The importance of the Fibonacci sequence is

that it returns in a lot of calculations

that occur in physics and even biology

A Fibonacci sequence is a sequence of integer numbers

that starts with 1

and then every number after the first two numbers of the sequence

is the sum of the two preceding ones.

The first 4 numbers of this sequence are

1, 1, 2 and 3.

Which explains this date of 11-23.

In other words: November 23!

The Fibonacci sequence is named after the Italian mathematician Leonardo of Pisa,

most famously known as Fibonacci.

He described the sequence in his 1202 book Liber Abaci*.
*Before this, the sequence was kind of known in several other works

dating even before the year 0.

But Fibonacci put it in a clear formula

**,**

thus making it clear and easy for use

in pretty much every science that deals with patterns.

**Popular uses of the Fibonacci sequence are:**

- The golden ratio in almost everything nature.

You can find the Golden ratio in every flower,

spiraling shells and even sleeping cats. - The golden ratio as a guideline in pictures.

Our eyes find it pleasing

when visuals are arranged in a way

that follows the golden ratio.

It is one of the most popular guide settings

when we take pictures with our phones. - DNA, the building blocks of every living creature,

follows the Fibonacci sequence

in how the DNA is build

and how they multiply and even mutate. - Fibonacci sequences are also used in written form.

Many Sanskrit documents wrote their prose and poetry

in patterns that followed parts of the Fibonacci sequence. - In mathematics the Fibonacci sequence

is one of the most practical recurring patterns,

just like the number pi. - Even in economics some predictions for trade

are made with Fibonacci retracement

You could say that

when humans found out

about the Fibonacci sequence,

we made a very important step

towards understanding the pattern

of nature itself.

*“Where there is matter, there is geometry.”*

— Johannes Kepler