Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/4
M:4/4
K:C
['G G c c G/G/']  
X:1
L:1/4
M:4/4
K:C
 G,/ | C C/-C/ E E | F F G G | c c G/G/ A | _B A G G | c c G/G/ G | F A G E | G G/-G/ F B,/-B,/ | 
 D2 C z/ ||  