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:G
['_BddcBA GGc_B/A/ G2 GBG_EDD CC=F_E D2 D^CD^FAG']  
X:1
L:1/8
M:3/4
K:G
 _BddcBA | GGc_B/A/ G2 | GBG_EDD | CC=F_E D2 | D^CD^FAG | D^CDFAG | _Bdd=cBA | c_B/A/ G3 F | 
 =FB G2 D2 | _EE D4 |]  