Musical Chord Progression Arpeggiator
Could someone explain what the basics are of this?  I'm not familiar with a lot of music theory.  The arpeggio is something like:    for base_note in range(B,B+5*2,2):
      for arpeggio_note in range(base_note,2*base_note,2):
        yield arpeggio_note

and the "chords" are single notes in some progression?  Something like (R, R+1, R+3, R+5, R+6, R+8, R+10), where R is the root note?What do the different modes do?