Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:2/4
K:A
['AB cAAf fedc dcBA BEEB cAAf feae', 'CEAc ecae']  
X:1
L:1/8
M:2/4
K:A
 AB | cAAf | fedc | dcBA | BEEB | cAAf | feae | cAEG | A2 :: ED | CEAc | ecae | cAEC | DB,B,E | 
 CEAc | ecae | cAEG | A2 :|  