Are you experienced in colour composition?! OK, then have a good look at the following picture...
Are the colours of the squares “A” and “B” the same?
NO? Have a closer look!...
Not convinced?! Go back if you want. Nobody has changed the colour of the squares. You have just witnessed an important phenomenon about the funcion of the brain...
The brain interpretes the squares as they should appear: Black or white, shown here as a dark and light gray. It completely disregards that they have the same shade! The opposite squares suggest 2 different colours... and your brain accepts this as a fact.
It shows that often we observe things not as they are but as we want them to be!