Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:2/2
K:D
['DFEF D2']  
X:1
L:1/8
M:2/2
K:D
"D" DFEF D2 Ad |"A" cAGE"G" EFGE |"D" DFEF D2 dB |"A" cAGE"G" AD D2 |"D" DFEF D2 Ad | 
"A" cAGE"G" EFGB |"D" Ad d2"G" dfed |"A" cAGE"D" ED D |] e |"D" f2 fe fdge |"D" fdge"A" afde | 
"D" f2 fe fage |"D" f2 ec"A" Adde |"D" f2 fe fdge |"D" fdge"A" afge |"D" fage"G" dfed | 
"A" dcAG EFGE |]  