Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/16
M:2/4
K:D
['FAde fgef dABd', 'ceae fecA BcBA BAFA ABAF']  
X:1
L:1/16
M:2/4
K:D
 (AG) | FAde fgef | dABd ABAF | ABde fefb | afdf edef | FAde fgef | dABd BABd | FAdf edef | 
 afef d2 :: (3efe | ceae fecA | BcBA BAFA | ABAF EFAc | fecA B2(3ege | ceae fecA | BcBA BAFA | 
 ABAF EFaf | ecBc A2!D.C.! :|  