Create a composition by utilizing the given alphabet-based musical pattern and the provided melodic theme.
X:1
L:1/8
Q:1/4=120
M:4/4
K:Bb
['BFDF Bdfd gfga b2 ag fdBd', 'dfBf dfBf']  
X:1
L:1/8
Q:1/4=120
M:4/4
K:Bb
"^NB" dc | BFDF Bdfd | gfga b2 ag | fdBd fdBd | cAFA cAFA | BFDF Bdfd | gfga b2 ag | fdBd ecAc | 
 B2 B2 B2 :: fe | dfBf dfBf | egcg egcg | dfBf dfB[df] | cAFA cAFA | dfBf dfBf | gfga b2 ag | 
 fdBd ecAc | B2 B2 B2 :|  