Count the number of 'F's in the following text:
FINISHED FILES ARE THE RE-
SULT OF YEARS OF SCIENTIF-
IC STUDY COMBINED WITH THE
EXPERIENCE OF YEARS

How many? Three?
Wrong. There are six - no joke!
Read again
The reasoning is further down
The brain cannot process the 'F's in "OF"
Incredible or what?
Anyone who counts all six 'F's on the first go is a genius -
three is normal, four quite rare.
Incredible eh!!!!!!