Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/8
M:4/4
K:A
['A/A/A{d} cA eAAf eAAa', 'aA A/A/A{d} cAAg aAAa']  
X:1
L:1/8
M:4/4
K:A
 c | A/A/A{d} cA eAAf | eAAa fe{d}dc | Bcde fBBg | aBBa gfea | A/A/A{d} cA eAAf | eAAa fedc | 
 defa fecf | ecBc f2 e || g | aA A/A/A{d} cAAg | aAAa fe{e}dc | bB B/B/B dBB^a | bBB=a gfeg | 
 aA A/A/A{d} cAAg | aAAa fedc | defa fecf | ecBd f2 ea ||  