Develop a musical composition in line with the given structure and theme.
X:1
L:1/8
M:4/4
K:Bb
['f4 d3 B (cA)', '[Af]3 (=e/f/g/a/) b4 g4 a4 f4 g2'  
X:1
L:1/8
M:4/4
K:Bb
 (B/c/d/e/) | f4 d3 B | (cA) FF F2 E2 | (DF) .B.B (Ac) (ed) | (gf) ed c4 | f4 d3 B | 
 (cA) .F.F F2 b2 | (3aga (3bag f2 Tg3/2f/4g/4 | [Af]2 f>f [Af]3 :: (=e/f/g/a/) | b4 g4 | a4 f4 | 
 g2 =e2 c2 B2 | [Af]2 F>F F2 E2 | D3 F BF BF | Ge e4 d2 | (3ded (3edc B2 Tc3/2B/4c/4 | B2 B>B B2 :|  