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
['DF Ad', 'af g{f}e']  
X:1
L:1/8
M:2/2
K:D
 ef |"D" af dB Ad FA | DF Ad f2 ef |"A7" g{f}e cB Ac e^g | a^g ab a2 f=g |"D" af dB Ad FA | 
 DF Ad f2 ef |"A7" g{f}e cB Ac ec |"D" df"A7" ec"D" d2 :: AF |"D" DF Ad (3BdB AF | DF Ad (3BdB A2 | 
"A7" A,C EA ce af | gf ed cB AF |"D" DF Ad (3BdB AF | DF Ad (3BdB A2 |"A7" A,C EA ce af | 
 g{f}e cA"D" d2 :|  