Create a composition by utilizing the given alphabet-based musical pattern and the provided melodic theme.
X:1
L:1/8
M:2/2
K:G
['', 'D GBdg egdB GBdg (3(efg) d |1', 'eAcA cdef gedB :|2 e2 (dB) cdef']  
X:1
L:1/8
M:2/2
K:G
 D |: GBdg egdB | GBdg (3(efg) d |1 g | eAcA eAcA | cdef gedB :|2 B | cdef gedc | BGAF G2 z2 |]: 
 dg (3(gfg) bg (3(gfg) | dgfg |1 (3(efg) (df) | eAcA eAcA | cdef gedB :|2 e2 (dB) | cdef gedc | 
 BGAF z2 |]  