Compose a musical piece using the designated musical pattern's alphabetic representation and the assigned melodic theme.
X:1
L:1/8
M:3/4
K:G
['(GB3/2) z/ (dcD) (FA3/2) z/', 'GBBd cD']  
X:1
L:1/8
M:3/4
K:G
 (GB3/2) z/ (dcD) | (FA3/2) z/ (c B2) | (GB3/2) z/ (dcD) | (FA3/2) z/ (F G2) :: GBBd cD | FAAc B2 | 
 GBBd cD | FAAD G2 :|  