Create a musical composition employing the given alphabetic structure and melodic theme.
X:1
L:1/8
M:4/4
K:C
['', '(3(BcB) AG', 'AG FADA', '']  
X:1
L:1/8
M:4/4
K:C
 .abc ||[M:2/2][K:G] dc"^segno" |: (3(BcB) AG (3(Bcd) AG | FADA FADc |1 (3(BcB) AG BdAG | 
 FDEF GBdc ||2 (3(BcB) AG (3(gfe) dc | BdAF G2 |: f2 |"^~" (g2 g)d BGBd | gfeg fgaf |1 
"^~" (g2 g)d (3(Bcd) AG | FADA FADF :|2 (3(fab) af gedc | BdAG FAdc"^segno" |]  