Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:4/4
K:G
['AcBA GE D2', 'g3 a bgaf', 'AcBA GE']  
X:1
L:1/8
M:4/4
K:G
 dG G2 dGeG | dGGA BAAB |1 dG G2 dedB | AcBA GE D2 :|2 GABd e2 dB | AcBA GE D2 || g3 a bgaf | 
 gfga bgef | g3 a bgaf | gfed Bdef | g3 a bgaf | gfga bgeg | bgaf gedB | AcBA GE D2 |: Bd d2 Bdgd | 
 Bdgd BA A2 |1 Bd d2 eBdB | AcBA GE D2 :|2 eB B2 gB B2 | AcBA GE D2 ||  