Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:6/8
K:D
['FDF AFA d2 A B3', 'dfa afa bag', 'AFA d2 A', 'afe def edB dfa af/g/a bag fge']  
X:1
L:1/8
M:6/8
K:D
 DED FDF | AFA d2 A | B3 BAB | dgf edB | ADD FDF | AFA d2 A | B3 AFA | dAF E3 :: dfa afa | 
 bag fef | dfa afe | def edB | dfa afa | bag fed | B2 B AFA | dAF E3 ::"^variations" D3 FDF | 
 AFA d2 A | B3 BAB | def edB | ADD F3 | AFA d2 A | BdB AFA |1 dAF EFE :|2 dAF EFA |: dfa afa | 
 bag fge | dfa afe | def edB | dfa af/g/a | bag fge | d2 B AFA |1 dAF EFA :|2 dAF EFE ||  