Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/4
M:2/2
K:G
['[B,G]3 [B,G]3', 'f e d c']  
X:1
L:1/4
M:2/2
K:G
 [B,D]3 | ([A,D-]/[B,D]/-) [B,D] [DD] | [B,G]3 | [B,G]3 | A/G/- G2 |{A} G (B, [DD]) | E3 | G c e | 
 d3 | B3 |{c} B A [GA] | [EA] ([FA-]/([EA-]/) [DA]) | [B,G]3 | [B,G]3/2 (A/ G) | B,2- B,/(B,/ | 
 A,) (B, D) | [B,G]3 | [B,G]3 | A/G/- G2 |{A} G (B, [DD]) | E3 | G c/e/- e | d3 |{e} d3 |{B} A2 F | 
 E (F/G/) A | [B,G]3 | [B,G]3 || g (B/d/-) d/g/- | g B/d/- d | [df]3 | [df] z z | [df]3 | 
 [df] a g | f e d | c (B/4c/4d/- d/)c/ | B3 | B3 | g (B/d/-) d/g/- | g B/d/- d | [df]3 | [df] z z | 
 [df]3 |{fg} f e d | c (B/4c/4B/ A) | [B,G]3 | ([B,G]3/2 A/) G ||  