Construct a musical piece by amalgamating the designated alphabetical representation and the supplied musical theme.
X:1
L:1/4
M:4/4
K:G
['G B', 'G B']  
X:1
L:1/4
M:4/4
K:G
 d2 | c d A B/A/ | G G F G | A"^(a)" B/A/ G G | G3 G | B G B c | d g f g | e d c e | d3 G | 
 B G B c | d g f g | e d c e | d2 B3/2 c/ | d e/d/ c d/c/ | B G F G | A B G G | G2 || d2 | 
 c d A B/A/ | G G F G | A"^(a) var." B G G | G3 G | B G B c | d g f g | e d c e | d3 G | B G B c | 
 d g f g | e d c e | d2 B3/2 c/ | d e/d/ c d/c/ | B G F G | A B G G | G2 |]  