Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:4/4
K:C
['FED (c/B/Ag) fed', 'fAg fed', '(a/g/f)a (g/f/e)g']  
X:1
L:1/8
M:4/4
K:C
 |[M:6/8][K:Glyd] TG | FED (c/B/Ag) | fed cAG | (A/B/A)(G A)Bc | dcA ABG | FED (c/B/Ag) | fed cAF | 
 TG3 GA(F | D)GG G2 :| | B | cBA fAg | fed cAG | (A/B/A)(G A)Bc | dcA ABG | FED fAg | fed cAF | 
 TG3 GA(F | D)GG G2 :| | f | (a/g/f)a (g/f/e)g | fed cAG | (A/B/A)(G A)Bc | dcA Afg | 
 (a/g/f)a (g/f/e)g | (f/e/d)(f e)cA | TG3 GA(F | D)GG G2 :|  