Let's start at the beginning. 12 months - 12 notes.... Folks like to imagine that they are using only 7 notes at a time, but in the end without multiplying by repeating in other registers and including demitones, there are 60 descernable tones.... Still without bending, we got a 12 note "musical calendar" to train our ear and mind, Also note when peeps like to think of using only 7 notes (being in a KEY) there are also "incidently" incidentals which is easiest to view the 6 omitted black keys as flats. Here is the vid: