# The Picture Book Colour Model - Walking along PI

There are thousands of ways to build a coloured world using Pi digits. For our edition we supposed two main shades that create a coloured region together with the dark black shade.
Two examples of possible colour spaces are given below:

Color 1: Red
Color 2: Light Green

Color 1: Yellow
Color 2: Light Cyan

The Picture Book starts with a middle gray shade for both main colours. Then - walking along the Pi digits - the two main shades slowly change, independently of each other because they receive their respective colour change information from 3 successive Pi digits each. A certain shade taken from the coloured space is then defined by the x/y coordinates in the coloured space which are derived from 4 successive Pi digits. Finally, this shade is used to paint the next square on the Picture Book matrix.

Detail from Page #2275 (Book P)

Leafing through the books of this edition one can follow the imperceptible colour change characteristics over consecutive pages. You will find the complete colour evolution at one glance in the Colour Index.
Each square in the Picture Book represents 10 successive Pi digits, therefore one complete page consisting of 100 x 100 squares relates to 100.000 digits. All in all the whole edition is a picturesque map of a walk along 390.000.000 Pi digits.

The whole edition before bookbinding