Construct a musical piece by amalgamating the designated alphabetical representation and the supplied musical theme.
X:1
L:1/8
M:4/4
K:G
['B2 A2']  
X:1
L:1/8
M:4/4
K:G
 D2 | G2 GG G2 Ac | B2 A2 G2 z G | A2 AA A2 Bd | c2 B2 A2 z d | BGBd c3 c | B2 dB A2 z D | 
 G2 BG A2 dc | B2 A2 G2 |]  