Design various chord structures to improve the overall harmony of the assigned musical composition.
|: af dB Ad FA | DF Ad f2 ef | (3gfe cB Ac eg | a^g ab a2 f=g | af dB Ad FA | 
 DF Ad f2 ef | (3gfe cB Ac ec | df ec d4 :: DF Ad (3BdB AF | DF Ad (3BdB A z | 
 A,C EA ce af | gf ed cB AF | DF Ad (3BdB AF | DF Ad (3BdB A z | A,C EA ce af | 
 (3gfe cA d2 FE :|  
X:1
L:1/8
M:2/2
K:D
|:"D" af dB Ad FA | DF Ad f2 ef |"A" (3gfe cB Ac eg | a^g ab a2 f=g |"D" af dB Ad FA | 
 DF Ad f2 ef |"A" (3gfe cB Ac ec |"D" df ec d4 ::"D" DF Ad (3BdB AF | DF Ad (3BdB A z | 
"A" A,C EA ce af | gf ed cB AF |"D" DF Ad (3BdB AF | DF Ad (3BdB A z |"A" A,C EA ce af | 
 (3gfe cA"D" d2 FE :|  