Compose a song that follows Bach's musical techniques.  
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 nm="Piano" snm="Pno"
%%MIDI program 0
%%MIDI control 7 100
%%MIDI control 10 64
V:2 treble nm="Piano" snm="Pno"
%%MIDI channel 3
%%MIDI program 0
%%MIDI control 7 100
%%MIDI control 10 64
V:3 treble nm="Piano" snm="Pno"
%%MIDI channel 4
%%MIDI program 0
%%MIDI control 7 100
%%MIDI control 10 64
V:4 bass nm="Piano" snm="Pno"
%%MIDI channel 5
%%MIDI program 0
%%MIDI control 7 100
%%MIDI control 10 64
V:1
 A B c c | d c B !fermata!B | c d e e | f e/d/ d2 | !fermata!c2 e d | e e d c | d !fermata!d d e | %7
 f f e d/e/ | e2 !fermata!d2 | A B c c | d d e !fermata!e | e e f e | d c/B/ B2 | !fermata!A4 |] %14
V:2
 E E E E | A/^G/ A A !fermata!G | A =G G G | F/G/ A G2 | !fermata!G2 G G | G c c/B/ c | %6
 c !fermata!B B A | A A A/G/ F | _B A/G/ !fermata!F2 | F E E/F/ G | A G G !fermata!G | %11
 E A A/ d ^c/ | d/^G/ A A G | !fermata!E4 |] %14
V:3
 C B, B,/A,/4^G,/4 A, | A,/B,/ C/A,/ E !fermata!E | E D D/C/4B,/4 C | C C C B, | !fermata!E2 C D | %5
 D C A/F/ G | G !fermata!G G G | F/E/ D ^C D | D ^C !fermata!A,2 | D D C C | C B, C !fermata!C | %11
 B,/D/ D/C/ C/_B,/4A,/4 G, | A,/B,/ C/F/ E3/2 D/ | !fermata!^C4 |] %14
V:4
"Am" A,"E/G#" ^G,"Am" A,3/2 =G,/ |"Dm/F" F,"Am/E" E,/D,/"Esus4" E,"E" !fermata!E, | %2
"Am" A,"G/B" B,"C" C3/2 B,/ |"F/A" A,"Fmaj7" F,"Gsus4" G,"G" G,, |"C" !fermata!C,2"C" C"G/B" B, | %5
"Em7/B" C/B,/"Am" A,/G,/"Dm7/F" F,/D,/"C/E" E,/C,/ |"Gsus4" G,"G" !fermata!G,,"G" G,"A7/C#" ^C, | %7
"Dm" D,/E,/"Dm/F" F,/G,/"A" A,"Bb" _B,/A,/ |"Em7b5/G" G,"A" A,"Dm" !fermata!D,2 | %9
"Dm" D"E7/G#" ^G,"Am" A,"C/E" E, |"Dm7/F" =F,"G" G,"C" !fermata!C,2 | %11
"E/G#" ^G,,"Asus4" A,,"Dm7" D,"Em" E, |"Dm/F" F,"Am/E" E,/D,/"Esus4" E,"E" E,, | %13
"A" !fermata!A,,4 |] %14  