Craft a piece of music that integrates both the suggested theme and letter-based structure.
X:1
L:1/8
M:6/8
K:D
['', 'd2 e fgf edc', 'fef A=ff', 'CDE Ddd Aee Aff Agg fed edc']  
X:1
L:1/8
M:6/8
K:D
 A3 |: AGF EDC | D3 d2 e | fgf edc | d3 d2 e | fgf edc | dAA BAG | FED EDC | DA,B, CDE | Ddd Aee | 
 Aff Agg | fed edc |1 d3 A3 :|2 d2 d d=c^A |: A=ff fef | A=ff fef | A=ff Agg | Aaa A_bb | 
 A=ff fef | A=ff f2 g | =fed ed^c |1 d2 d d=c^A :|2 d3 z2 e |: fgf edc | dAA BAG | FED EDC | 
 DA,B, CDE | Ddd Aee | Aff Agg | fed edc |1 d3 z2 e :|2 d6 ||  