Create a musical composition based on the alphabetic representation of the predetermined pattern and the given melodic theme.
X:1
L:1/8
M:3/4
K:D
['da ag gf fe ed dc dc', 'd2 fd fa c2 ec eg']  
X:1
L:1/8
M:3/4
K:D
 da ag gf | fe ed dc | dc B2 g2 | f/e/d/c/ d2 D2 :: d2 fd fa | c2 ec eg | d2 fd fa | c2 ec eg | 
 fe/f/ ge/g/ fe/d/ | c/d/e/c/ d2 D2 :|  