Construct a musical piece by amalgamating the designated alphabetical representation and the supplied musical theme.
X:1
L:1/8
Q:1/8=180
M:6/8
K:G
['g2 G GAG BcB def', 'fed gbg dBd ege dBG']  
X:1
L:1/8
Q:1/8=180
M:6/8
K:G
|: g2 G GAG | BcB def | g2 g bag | faf def | g2 G GAG | BcB def | gfg bag | fag fed :: gbg dBd | 
 ege dBG | gag dBd | eag fed | gbg dBd | ege dBG | gfg bag | fag fed :|  