Develop a harmonious composition using Bach's signature techniques.  
X:1
T:Music21 Fragment
T:Music21 Fragment
T:Music21
C:Music21
%%score 1 2 3 4
L:1/4
M:3/4
K:C
V:1 treble 
%%MIDI program 0
%%MIDI control 7 100
%%MIDI control 10 64
V:2 treble 
%%MIDI program 0
%%MIDI control 7 100
%%MIDI control 10 64
V:3 treble 
%%MIDI program 0
%%MIDI control 7 100
%%MIDI control 10 64
V:4 bass 
%%MIDI program 0
%%MIDI control 7 100
%%MIDI control 10 64
V:1
 A A A | e3/2 d/ c | e d c | !fermata!B3 | e e ^f | g2 ^f | e ^d2 | !fermata!e3 | e d B | %9
 c3/2 d/ e | d c B | !fermata!c3 | g a g | e3/2 d/ c | B A ^G | !fermata!A3 |] %16
V:2
 E A/B/ c | B2 A | A ^G A | !fermata!^G3 | A/B/ c c | B2 A | G ^F2 | !fermata!^G3 | A =F E | %9
 E A G | A G G | !fermata!G3 | c c B | B2 A | F E E | !fermata!E3 |] %16
V:3
 C E E | E2 E/D/ | C D E | !fermata!E3 | E A A | G ^C ^D | E B,2 | !fermata!B,3 | C B, B, | %9
 A, F E | F E D | !fermata!E3 | E D D | B, E E | D C B, | !fermata!^C3 |] %16
V:4
"Am" A,/B,/"Am/C" C"Am/B" B,/A,/ |"E/G#" ^G,2"Am" A, |"Am/C" C,"G#dim/B" B,,"Am" A,, | %3
"E" !fermata!E,3 |"Am/C" C"Am/B" B,/A,/"D#dim7" ^D, |"C#m7b5/E" E,2"D#dim/F#" ^F, | %6
"Apower" G,/A,/"B" B,"B" B,, |"E" !fermata!E,,3 |"Am" A,,"Bm7b5/A" A,"E/G#" ^G, | %9
"Am" A,3/2 B,/"C" C |"Dm/F" F,"C/G" G,"G" G,, |"C" !fermata!C,3 |"C" C"Dm7/F" F,"G" G, | %13
"E/G#" ^G,2"Am" A, |"Bdim/D" D,"Am/E" E,"E" E,, |"A" !fermata!A,,3 |] %16  