Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:3/4
K:D
['FE DE FG', '[FA][GA] A2 [Af]3 [Aa] [Af]2 e2 d2']  
X:1
L:1/8
M:3/4
K:D
 FE | DE FG FE |{EF} E2 D2 FE | DE FG A2 | [EA]4 [EA]F | E2 [Ec]3 [Ed] | ([E-c][EB]) [EA]3 (B | 
 c2) B2 A2 | [FA]4 FE | DE FG FE | D4 FE | DE FG A2 | [EA]4 [EA]F | E2 [Ec]3 [Ed] | 
 ([E-c][EB]) [EA]3 EF | G2 F2 ED | !slide![DD]4 |: [FA][GA] | A2 [Af]3 [Aa] | [Af]2 e2 d2 | 
 GA B2 d2 | B4 cB | [AA]2 [Ac]3 d |1 cB A3 (A | B2) A2 [GA]2 | [FA]4 :|2 cB A2 [EA][FA] | 
 G2 [FA]2 [EA]2 | [DD]4 ||  