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:A
['f2 cf ecBc', 'B3 c']  
X:1
L:1/8
M:4/4
K:A
[K:F#min] | f2 cf ecBc | f2 ce faga | f2 cf ecBc | AF (3ABc e3 a | f2 cf ecBc | f2 ce faga | 
 f2 cf ecBc | AF (3ABc ecBA || B3 c BAFE | (3FGA Bc B3 c | BABc dcde | (3fga gf ecBA | B3 c BAFE | 
 (3FGA Bc B3 A | BABc dcde | (3gab ag fece ||  