 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