Compose a piece of music using the specified alphabetical notation system and the provided theme.
X:1
L:1/8
M:4/4
K:Bb
['', 'B/B/B B2', 'A<F f>B e/d/c/B/ f<B']  
X:1
L:1/8
M:4/4
K:Bb
 F |: B/B/B B2 B>df>d | B/B/B B2 c>B A<F | B/B/B B2 B>df>d | e<gd<f c>B A<F :: 
 f>B e/d/c/B/ f<B e>g | fB e/d/c/B/ c>B A<F | f>B e/d/c/B/ f<B d>f |1 e<gd<f c>B A<F :|2 
 e<gd<b c>B A<F |]  