Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/16
Q:1/4=100
M:2/4
K:D
['BdAd eada caBa AaBa caBa', 'D2 A2 ^GAEa fdAf gAfA ecdA ^GAEA']  
X:1
L:1/16
Q:1/4=100
M:2/4
K:D
 (3(ABc) | d2cd BdAd | eada caBa | AaBa caBa | (^ga)ea fdAF | z .d(cd) BdAd | eada caBa | 
 AaBa caBa | fdAF D2 :: A2 | ^GAEa fdAf | gAfA ecdA | ^GAEA FADA | Beec dBA^G | Aada fdcd | 
 gefd edcd | ecAe fedc | Bedc d2 :|  