Craft a piece of music that integrates both the suggested theme and letter-based structure.
X:1
L:1/8
M:3/4
K:Bb
['cg d2 f2']  
X:1
L:1/8
M:3/4
K:Bb
 cg d2 f2 | ec B2 df | cg d2 f2 | e>c B2 F2 | Fc B2 d2 | e3/2cB3/2 d2 | Fc B2 d2 | ec B2 F2 |]  