Compose a melody in the style of Bach.  
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
L:1/8
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
L:1/8
V:1
 z3 c/d/ | e f g f | e d !fermata!e e | e d/e/ f/e/ d | c/>d/ d !fermata!c c/d/ | e f g f | %6
 e d !fermata!e e | e d/e/ f/e/ d | c/>d/ d !fermata!c c | d e f e | d3/2 ^c/ !fermata!d d | %11
 e f g f | e d !fermata!e e | e d/e/ f/e/ d | c/>d/ d !fermata!c z |] %15
V:2
 z6 GB | c2 c2 B2 AB | c2 cB !fermata!c2 c2 | c2 Bc dc B2 | c2 cB !fermata!G2 GB | c2 c2 B2 AB | %6
 c2 cB !fermata!c2 c2 | c2 Bc dc B2 | c2 cB !fermata!G2 G2 | G2 G2 A2 A2 | AF _BA !fermata!A2 =B2 | %11
 c2 _B2 A2 A=B | c3 B/A/ !fermata!^G2 A2 | GA Bc d c2 B | AG AG !fermata!G2 z2 |] %15
V:3
 z3 E/F/ | G A D D | G G !fermata!G A | G G A/G/ G/F/ | E A/G/4F/4 !fermata!E E/F/ | G A D D | %6
 G G !fermata!G A | G G A/G/ G/F/ | E A/G/4F/4 !fermata!E E | D C C ^C | D G !fermata!F D | %11
 G F E F/G/ | A A, !fermata!B, C/D/ | E/F/ G/C/ B,/C/4B,/4 A,/B,/ | C3/2 B,/ !fermata!E z |] %15
V:4
 z6"C" C,2 |"C" CB,"F/A" A,2"G" G,2"Dm" D,2 |"C/E" E,F,"Gsus4" G,2"C" !fermata!C,2"Am" A,2 | %3
"C/E" E,F,"G" G,2"Dm" D,E,"G7/F" F,G, |"Am" A,G,"Dm7/F" F,G,"C" !fermata!C,2"C" C,2 | %5
"C" CB,"F/A" A,2"G" G,2"Dm" D,2 |"C/E" E,F,"Gsus4" G,2"C" !fermata!C,2"Am" A,2 | %7
"C/E" E,F,"G" G,2"Dm" D,E,"G7/F" F,G, |"Am" A,G,"Dm7/F" F,G,"C" !fermata!C,2"C" C2 | %9
"G/B" B,2"C7/Bb" _B,2"F/A" A,2"A7/G" G,2 |"Dm/F" F,_B,"Gm" G,A,"Dm" !fermata!D,2"G" G,F, | %11
"C/E" E,2"Bb/D" D,2"A7/C#" ^C,2"Dm" D,2 |"Am" A,G,"Dm7/F" F,2"E" !fermata!E,2"Am" A,B, | %13
"C" C2"G/B" B,A,"G#dim7" ^G,A,"D7/F#" ^F,G, |"Am" A,E,"Dm7/F" F,G,"C" !fermata!C,2 z2 |] %15  