Write a musical work incorporating the specified theme and letter-based framework.
X:1
L:1/8
Q:1/2=100
M:2/2
K:Bb
['ba b2 f2 f2 e2 d3 c', 'c6 fg f2 c2 c2 B2 A3']  
X:1
L:1/8
Q:1/2=100
M:2/2
K:Bb
 ba | b2 f2 f2 e2 | d3 c B2 gf | gfgf gfed | c6 :: fg | f2 c2 c2 B2 | A3 G F2 BA | BdBd G2 cB | 
 cece A2 GF | GA B2 B3 A | B6 :|  