Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
Q:1/8=180
M:4/4
K:C
['FEFG ABcB', 'fdeg fdec']  
X:1
L:1/8
Q:1/8=180
M:4/4
K:C
[M:4/4][K:G] a e ue!p! aed da"^D modal" .E | FEFG ABcB | Addc AddE | FEFG ABcB | GBAG FDDE | 
 FEFG ABcB | Addc Adde | fage fdec | ABAG FDD || g | fdeg fdec | Addc Adde | fdeg fdec | 
 ABAG FD D2 | fdeg fdec | Addc Adde | fage fdec | ABAG FDD |]  