Construct a musical piece that follows the designated lettered structure and integrates the provided motif throughout.
X:1
L:1/8
M:7/8
K:D
['AG F2']  
X:1
L:1/8
M:7/8
K:D
"D" F2 G AB AG |"D" F3- F4 |"D" F2 G AB AG |"D" F2 E FE D2 |"Bm" D3 EF ED |"A" E3- E4 | 
"D" F3"A7" EF ED |"D" D2 F FG AG |"D" F2 F"A7" E2 ED |"D" F3 FG AG |"D" F2 F"A7" E2 E2 | 
"D" D3"_tune in lowest part" [FA][GB] [Ac][GB] |"D" [FA]2 [FA]"A7" [EG]2 [EG][DF] | 
"D" [FA]3 [FA][GB] [Ac][GB] |"D" [FA]2 [FA]"A7" [EG]2 [EG]2 |"D""D" [DF]3- [DF]2 |]  