Circles means “circle of 5ths”, a sort of exercise that musicians practice in order to perfect their ability in playing easily in different keys. This piece is really an exercise, and it’s dedicated to musicians, with the spirit that even such practice can evoke some music that’s at least a little interesting. The improvising is the meaning of the song with the simple melody giving room, benchmarks, for the circling chords showing up to do their job 2 or 3 times a bar. You can use this format for your own practice. Just start in C-minor.