Craft a piece of music that integrates both the suggested theme and letter-based structure.
X:1
L:1/8
Q:1/8=160
M:6/8
K:D
['FAD DEF AFD FED', 'FED FAF', 'dAF G3 GFE A3 ABc dBd cAc']  
X:1
L:1/8
Q:1/8=160
M:6/8
K:D
 FAD DEF | AFD FED | FAD DFG | A2 A BGE |"^5" FAD DEF | AFD FED | E2 E dAF | G3 GFE :: 
"^9" D2 d dcd | F2 A AFA | D2 d dcd |1 A2 A BGE |"^13" D2 d dcd | F2 A AFA | BdB cAF | G3 GFE :|2 
"^12a" ABA ABc | dcB cBA | BAG AGF | E2 E dAF | G3 GFE |:"^17" FED FAF | GBG FAG | FED FAF |1 
 A2 A BGE |"^21" FED FAF | GBG FAF | E2 E dAF | G3 GFE :|2"^20a" A3 ABc | dBd cAc | BdB AGF | 
 E2 E dAF | G3- G3 |]  