Create a musical composition employing the given alphabetic structure and melodic theme.
X:1
L:1/8
M:2/4
K:Bb
['DF Bd', 'B2 f bf gf bB cB Gc']  
X:1
L:1/8
M:2/4
K:Bb
 F | DF Bd | fg fd | eg Gc | Ac cd | DF Bd | fd bd | ec Af | dB B2 :: f | bf gf | bB cB | Gc cB | 
 Ac ce | df Bd | GB Eg | fb ce | dB B2 :|  