Create a composition by utilizing the given alphabet-based musical pattern and the provided melodic theme.
X:1
L:1/8
M:2/4
K:Bb
['FE DF', 'B2 FE DFBF GFED ECcB AGFE DFBd']  
X:1
L:1/8
M:2/4
K:Bb
 FE | DF B4 FE | DF B,4 FD | CE c2 cdcB | Ac F4 cd | edef gebg | dcde fdbf | egce AcFA | 
 B2 d2 B2 :| FE | DFBF GFED | ECcB AGFE | DFBd edcB | AcBG F2 FG | AGAB c=Bcd | edef g2 (3fed | 
 fbdf BdFA | B2 d2 B2 :|  