Design various chord structures to improve the overall harmony of the assigned musical composition.
DFA d3 | ecA cde | f3 g3 | ecA GFE | DFA d3 | ecA cde | faf gec | 
 edc d3 :: dfa agf | efg efg | fef gfg | ecA GFE | DFA d3 | ecA cde | 
 faf gec | edc d3 :|  
X:1
L:1/8
M:6/8
K:D
"D" DFA d3 |"A7" ecA cde |"D" f3"G" g3 |"A7" ecA GFE |"D" DFA d3 |"A7" ecA cde |"D" faf"A7" gec | 
 edc"D" d3 ::"D" dfa agf |"A7" efg efg |"D" fef"G" gfg |"A7" ecA GFE |"D" DFA d3 |"A7" ecA cde | 
"D" faf"A7" gec | edc"D" d3 :|  