Assemble a piece of music by merging the alphabetic representation of the predetermined musical pattern and the provided melodic theme.
X:1
L:1/8
M:4/4
K:G
['B2 AG', '', 'B2 Bc A4 GB dc B4 d2', 'Bddd ceee', 'B3 c']  
X:1
L:1/8
M:4/4
K:G
 D | GBdc B2 AG | BA GF G2 D2 | GB dc B2 AG | BAGF G3 :| z |: B2 Bc A4 | GB dc B4 | d2 ef gd ec | 
 B2 A2 G4 | B2 Bc A4 | GB dc B4 | d2 ef gdec | Bd AF G4 :: Bddd ceee | defd g2 g2 | Bddd ceee | 
 defd g4 :: B3 c d4 | efge e2 d2 | B3 c d2 B2 | ec AF G2 G2 | B3 c d4 | efge edcB | B3 c d2 B2 | 
 ec AF G4 :|  