Create a composition by utilizing the given alphabet-based musical pattern and the provided melodic theme.
X:1
L:1/8
Q:1/8=128
M:4/4
K:Bb
['B,2 B,>B BA GF']  
X:1
L:1/8
Q:1/8=128
M:4/4
K:Bb
|: F | B,2 B,>B BA GF | G>F GB cC CD | B,2 B,>B BA GF | G/A/B c/d/e dB BD | B,2 B,>B BA GF | 
 G>F GB cC CD | B,2 B,>B BA GF | G/A/B c/d/e dB Bd/e/ | f>B f>d fB g>f | fB f>d dc cd/e/ | 
 f<B f>d f<B g>B | F>B cB/c/ dB Bd/e/ | f>B f>d fB g>f | fB f>d dc cd/e/ | B,2 B,>B BA GF | 
 G/A/B c/d/e dB B :|  