Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:3/4
K:D
['A3 A3']  
X:1
L:1/8
M:3/4
K:D
|:"D" A>B A d2 d |"A" e>f e a3 |"D" f>e f"G" B2 B |1 B3"A" A3 :|2"A" A3 A3 |:"Bm" f>d f f3 | 
"Em" e>B e e3 |"Bm" d>B c"G" d2 c |1"Bm" B3 B3 :|2"Bm" B3"A" A3 ||  