Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:6/8
K:G
['AAAd^cB A2 A F2 A A>GGGAB B3']  
X:1
L:1/8
M:6/8
K:G
 D | DGGGFE | EDD D2 D | DGGGAB | B3 A2 G | AAAd^cB | A2 A F2 A | A>GGGAB | B3 AzG | AAAd^cB | 
 A2 A F2 A | A>GGGAB | B3 A z |]  