Write a composition that embodies the spirit of Bach's music.  
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
 d d d d | c _B !fermata!A2 | _B c d d | c _B !fermata!A2 | G A _B G | G/F/ _E !fermata!D2 | %6
 _E F G G | F _E !fermata!D2 | G ^F G A | _B A/G/ !fermata!G2 | _B c d d | c _B/A/ !fermata!A2 | %12
 G A _B/A/ G | G/F/ _E !fermata!D2 | _E F G G | F _E D2 | !fermata!D4 |] %17
V:2
 ^F F G A | G G !fermata!^F2 | D _E F F | _E D !fermata!D2 | D D D _E | D C !fermata!=B,2 | %6
 C C _D D | C2 !fermata!=B,2 | D C D _E | D D !fermata!_E2 | F F F G | G2 !fermata!^F2 | D D D _E | %13
 D C !fermata!=B,2 | C D _E E | D C2 _B, | !fermata!A,4 |] %17
V:3
 A, A, _B, A,/B,/ | C/D/ _E !fermata!A,2 | G, G, _A, G, | G,2 !fermata!^F,2 | _B, A, G,/A,/ B,/C/ | %5
 D/G,/ G, !fermata!G,2 | G, _A, _B, B, | _A,/_B,/ C !fermata!G,2 | _B, A, G, G, | %9
 G,/F,/ _B, !fermata!B,2 | D A, _B, B, | C/D/ _E !fermata!D2 | G, ^F, G,/A,/ _B,/C/ | %13
 D/G,/ G, !fermata!G,2 | G, _B, B, B, | _B,/_A,/ G, ^F, G, | !fermata!^F,4 |] %17
V:4
"D" D,"D" D,"Gm" G,"Dm/F" =F, |"Cm/Eb" _E,"Ebmaj7/D" D,/C,/"D" !fermata!D,2 | %2
"Gm" G,"Cm/Eb" _E,"Bdim7" =B,,"G7/B" B,, |"Cm" C,"Gm" G,,"D" !fermata!D,2 | %4
"Gm" G,"D/F#" ^F,"Gm" G,"Eb" _E, |"G/B" =B,,"Cm" C,"G" !fermata!G,,2 | %6
"Cm" C,"Fm/Ab" _A,,"Edim7" =E,,"Edim7" E,, |"Fm" F,,"F#m" ^F,,"G" !fermata!G,,2 | %8
"Gm" G,,"F#dim/A" A,,"Gm/Bb" _B,,"Am7b5/C" C, |"Gm/D" D,"Bb" _B,,"Eb" !fermata!_E,2 | %10
"Bb/D" D,"F" F,"Bb" _B,/A,/"Gm" G,/F,/ |"Cm/Eb" _E,"Ebmaj7/D" D,/C,/"D" !fermata!D,2 | %12
"Gm/Bb" _B,,"D" D,"Gm" G,/=F,/"Eb" _E, |"G/B" =B,,"Cm" C,"G" !fermata!G,,2 | %14
"Cm" C,"Bb" _B,,"Eb" _E,,/F,,/"Eb/G" G,,/_A,,/ |"Bb" _B,,"Cm" C,"D" D,2 |"D" !fermata!D,4 |] %17  