Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:2/4
K:D
['d2 d>e fd AD/F/ AA A/^A/B/c/ .d2', 'cd e2 d2 c2 B2', '.F2 BB/B/ BB BG G2 BA/A/ AG/G/']  
X:1
L:1/8
M:2/4
K:D
"D" d2 d>e | fd AD/F/ |"A7" AA A/^A/B/c/ |"D" .d2 z d/B/ |:"Em/G" dc/c/ cG |"A7" c3 c/G/ | 
"D" BA/A/ AF | A3 B/F/ |"A7" .G !>!G2 .A | Bc de |"D" f2 d>B | A2 z d/B/ |"Em/G" dc/c/ cG | 
"A7" c3 c/G/ |"D" BA/A/ AF | A2 z (3(A/^G/F/) |"A" E2 e>^d | .f !>!e2 d/c/ |"E7" cB d^G |1 
"A" AA/A/ Ad/B/ :|2"A" AA B>A |:"A7" A3 B | cd e^e |"D" .f2 (!>!d2 | d)F G>F |"F#7" F3 ^G | 
 ^AB cd |"Bm" .e2 (!>!d2 | d)d cd |"G" e2 d2 | c2 B2 |"D" (A4 | A)A ^GA |"A7" c3 B |"F#7" ^AG FE | 
"Bm" .E2 (!>!D2 |"D7" D)d cd |"G" e2 d2 |"Em" c2 B2 |"D/A" Af (d2 | d)d cB |"A7" A3 A/^A/ | cB GE | 
"D" D2 d>d |1 dA B>A :|2"G7" d2 z2 ||[K:C]"C" GG/G/ GG | GE E2 | Ge d/c/B/A/ |"G7" G2 .F2 | 
 BB/B/ BB | BG G2 | BA/A/ AG/G/ | G3 F |"C" GG/G/ GG | GE E2 | Gc/B/ cB |"F" B2 .A2 | f3 e/d/ | 
"C/G" e3 d/c/ |"G7" .c !>!B2 A/B/ |"C" cc c2 |]  