Craft a composition that integrates the assigned alphabet-related musical pattern and the provided melodic theme.
X:1
L:1/8
Q:3/8=100
M:6/8
K:Dmix
['fef ded cAB c2 d cBA GFG', 'd2 A dfa afd dfa a2 f']  
X:1
L:1/8
Q:3/8=100
M:6/8
K:Dmix
 a/g/ | fef ded | cAB c2 d | cBA GFG | Add d2 e | fef ded | cAB c2 d | cBA GFG | Add d2 :: A | 
 dfa afd | dfa a2 f | gef ged | cef g2 e |{g} fef ded | cAB c2 d | cBA GFG | Add d2 :|  