Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:6/8
K:C
['g3 ece g3 fdf ege cec BdB', 'c3 d3 BGB dfe fed efg afd']  
X:1
L:1/8
M:6/8
K:C
|: g3 ece | g3 fdf | ege cec | BdB GAB | cBc AGA | FEF Ddf | edc GAB | c3 c3 :: d3 BGB | dfe fed | 
 efg afd | gec BAG | AFA dfd | BGB ceg | Afe dcB | c3 c3 :|  