Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
Q:1/2=75
M:2/2
K:C
['C E2 e2 efgf dcBA G2 AB', 'e2 ef']  
X:1
L:1/8
Q:1/2=75
M:2/2
K:C
 C |[K:G]"^18" E2 e2 efgf | dcBA G2 AB | c2 B2 edcB | A3 G E4 :: d2 | e2 ef g2 fg | 
 agfe"^1" d2 cd | e2 a2 a3 b | a3 g e2 ef | gfga g2 fe | dcBA G2 AB | c2 B2 edBA | A3 G E4 :|  