Develop a musical composition using the outlined alphabetical depiction of the structure and the provided theme.
X:1
L:1/8
M:4/4
K:G
['(3def gGGG BGdB ABcd edef', 'G2 dc BGDG BBGB ABcd eedc BGDG']  
X:1
L:1/8
M:4/4
K:G
 (3def | gGGG BGdB | ABcd edef | gGGG BGdG | eGfG g2 (3def | gGGG BGdB | ABcd edef | gfed edcB | 
 cedB G2 :: dc | BGDG BBGB | ABcd eedc | BGDG BGdG | eGfG gddc | DGGG BGAG | FGAB cdef | 
 gfed edcB | cedB G2 :|  