Develop a musical composition using the outlined alphabetical depiction of the structure and the provided theme.
X:1
L:1/8
Q:3/8=100
M:6/8
K:C
['c>dc cGE ceg g2 f', 'ceg gec']  
X:1
L:1/8
Q:3/8=100
M:6/8
K:C
 G | c>dc cGE | ceg g2 f | e>fe edc | Bdc BAG | c>dc cGE | ceg g2 f | efe fdB | c3- c2 :: c | 
 ceg gec | cfa afd | ceg gec | BGG G2 z | cde efg | def fga | gec GAB | c3- c2 :|  