Produce a melody that exemplifies the central qualities of Bach's compositions.  
X:1
T:Music21 Fragment
T:Music21 Fragment
T:Music21
C:Music21
%%score 1 2 3 4
L:1/4
M:4/4
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 bass 
%%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
 z3 C/D/ | E F G G | F E !fermata!D G | A B c B | A2 !fermata!G C/D/ | E F G G | F E !fermata!D G | %7
 A B c B | A2 !fermata!G G | c B A G | F E !fermata!D G | F E D/E/ F | E D !fermata!C z |] %13
V:2
 z3 G, | C C D C/B,/ | A,/B,/ C !fermata!B, D | E/^F/ G A G | G ^F !fermata!D G, | C C D C/B,/ | %6
 A,/B,/ C !fermata!B, D | E/^F/ G A G | G ^F !fermata!D D | E D C/D/ E | %10
 D G,/A,/ !fermata!B, E/D/ | C/ D C B,/ C | C B, !fermata!G, z |] %13
V:3
 z3 E,/F,/ | G, F,/E,/ D, E, | F, G, !fermata!G, G, | C D D D | E D/C/ !fermata!B, E,/F,/ | %5
 G, F,/E,/ D, E, | F, G, !fermata!G, G, | C D D D | E D/C/ !fermata!B, B,/A,/ | %9
 G,/E,/ F,/G,/ A, A, | A,/B,/ C !fermata!G, B, | A,/G,/ G, G, F, | G,3/2 F,/ !fermata!E, z |] %13
V:4
 z3"C" C, |"C" C,/B,,/"F/A" A,,"G/B" B,,"C" C, |"Dm" D,"C/E" E,/F,/"G" !fermata!G,"G" B, | %3
"Am" A,"G" G,"D7/F#" ^F,"G" G, |"Am7/C" C,"D" D,"G" !fermata!G,,"C" C, | %5
"C" C,/B,,/"F/A" A,,"G/B" B,,"C" C, |"Dm" D,"C/E" E,/F,/"G" !fermata!G,"G" B, | %7
"Am" A,"G" G,"D7/F#" ^F,"G" G, |"Am7/C" C,"D" D,"G" !fermata!G,,"G" G,/F,/ | %9
"C/E" E,/C,/"Bdim/D" D,/E,/"F" F,/E,/"A7/C#" D,/^C,/ |"Dm" D,"C/E" E,/^F,/"G" !fermata!G,"Em" E, | %11
"F/A" A,,/B,,/"C" C,"Gsus4" G,,"F/A" A,, |"C/G" G,,/F,,/"G" G,,"C" !fermata!C,, z |] %13  