In the circle of fifths diagram, the ascending circle of fifths moves clockwise,
while the descending circle of fifths moves counter-clockwise.
If you start at any point on the circle and go through 12 consecutive fifths,
you'll end up at the note you started from and will use all 12 chromatic pitches
in the process.
The order that sharps and flats occur in the key signature and the names of
the major and minor keys, in order of the increasing number of sharps or flats
used in the key signature, are based on the circle of fifths.
