Assemble a piece of music by merging the alphabetic representation of the predetermined musical pattern and the provided melodic theme.
X:1
L:1/4
M:4/4
K:G
['B B', 'd B']  
X:1
L:1/4
M:4/4
K:G
 g | d c/B/ c/B/A/G/ | B B B g | d c/B/ c/B/A/G/ | B A A G/A/ | B B c/B/A/G/ | G G g f/g/ | 
 a g/f/ g f/e/ | d B B :| B/c/ | d B g B/c/ | d B B g | d B g f/g/ | a A A G/A/ | B B c/B/A/B/ | 
 G G g f/g/ | a g/f/ g f/e/ | d B B :|  