monkey see, monkey doo

I have here a simple FAQ answer to Robert Walker's "Newbie" question.

Is it dumb enough? I think probably so...

Q. Why does the 12 tone scale have 12 notes, and why are there "black
and white" keys on the piano?

A. Our "common" 12 note system, such as one would see on a modern
piano, stems from a "Pythagorean" system which uses a string of
"pure," (unbeating) fifths. This system was developed in the Middle
Ages, in response to the use of pure fifths as a basic consonance.

A cycle of fifths will go "once around" 11 times before, eventually,
approximating an octave at the 12th fifth. (It doesn't quite…
see "Pythagorean comma")

If one were to transpose the pitches of this chain to within one
octave, one gets the 12 notes we presently use. The "closest" fifths
to the starting point were given "white" keys and those further away
and generally less used, were given "black keys."