Construct a musical piece by amalgamating the designated alphabetical representation and the supplied musical theme.
X:1
L:1/8
M:6/8
K:G
['GGG d2 d e2 f g2 d', 'def g2 d d2 c']  
X:1
L:1/8
M:6/8
K:G
 GGG | d2 d e2 f | g2 d gag | fgf efe | d3 :: def | g2 d d2 c | B2 B BcB | AGA BcB | TA2 G def | 
 g2 d d2 c | B3 d2 B | c2 B AGF | G3 :|  