Create a musical composition adhering to the provided thematic and alphabetical guidelines.
X:1
L:1/8
M:4/4
K:Bb
['d2 d2 BG F4 B2 z2 c2']  
X:1
L:1/8
M:4/4
K:Bb
"Bb" d2 d2 d>c"Eb" BG |"Bb" F4 B2 z2 |"F" c2 c2"Bb" d>c Bd |"F" c4 z2"F7" F>E | 
"Bb" DF B>c B2"Bb7" B>A |"Eb" GA B>G"Bb" F2"F" d>c |"Bb" BA B>G"F" (AB"F7" c)d |"Bb" B4 z4 |]  