But before talking about this evolution,

let's go back in time,

a few centuries actually.

I want to share with you an old legend about the game of chess,

not only because chess is the strategist preferred game but because

the story around the game creation will help us understand what digital is all about.

Surprising, isn't it? So, once upon a time,

there was an Indian king, a fighter,

who went into many battles.

One day, coming back from an exhausting fight,

he learned that he lost his son in the field.

He felt immense sadness and decided to withdraw into his castle.

This lasted for months then years until

one of his subjects named Lahur Sessa offered him a chessboard.

The king liked the game so much that he decided to grant the man whatever,

whatever he asked for.

Sessa kindly and humbly explained that he would like to

have one grain of rice for the first square of the chessboard,

two grains for the second square,

four grains for the third then eight grains and so on until the 64 squares are exhausted.

Before telling you the end of the story,

I want you to estimate how much rice did Sessa ask for.

First, without doing any actual calculation,

what is your intuitive guess?

Would it be as heavy as soccer ball for example?

A dairy cow or a Boeing 747 fully loaded?

You can pause for a few seconds to really see in your mind what is the intuitive answer.

Now, if you do the calculation,

you would see it was about two multiplied by 10 to the power of 19 grains,

which is in the same order of magnitude as the total Earth biomass.

Well, I cheat a little bit on the options but the reality is,

almost everyone's intuition would have been massively underestimating the amount.

This is because our minds are more

adapted to estimating linear change than exponential change.

Linear change is when we move from 1 to 2 to 3 or to spice it up,

from 2 to 4 to 6.

At step number n, we are at 2 multiplied by

n. This hour twitching can estimate pretty accurately.

Exponential change, however, is when at step number n,

we are at 2 to the power of n. So we move from 2 to 2 to 4 to 8, 16, 32, 64.

Because our intuition doesn't handle this representation,

we have a way to show it.

We call it algorithmic scale or log scale for short.

In this representation, the vertical axis itself goes

from 1 to 2 to 4, doubling every step.

In this representation, when you see a line,

it means you have an exponential growth,

the kind of growth Sessa has asked for after all.

For those who are interested to hear the end of the story,

well, there are two versions.

One where the king rewards the clever ask reasonably and one where,

well, Sessa doesn't live very long.