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:3/4
K:D
['f4 g2 afgb a2 b2 a2 g2', 'e6 e4 f2 gecA b2 a2 g2']  
X:1
L:1/8
M:3/4
K:D
 f4 g2 | afgb a2 | b2 a2 g2 | f4 e2 | gfge f2 | c2 BA d2 | BAGFEg | e6 :: e4 f2 | gecA b2 | 
 a2 g2 f2 | e2 dcBA | BABd c2 | d4 e2 | f2 d2 c2 | d6 :|  