Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/8
M:6/8
K:F
['', 'FAA GBB FAA B2 d', 'FAc f2 _e/ e/ dBB B2']  
X:1
L:1/8
M:6/8
K:F
 F |: FAA GBB | FAA B2 d | FAA BGc | AFF F2 c | FAA GBB | FAA B2 d | cBA GAB | AFF F2 F :: 
 FAc f2 _e/ e/ | dBB B2 B | GBd g/ g3/2 f | ecc c2 A | FAc f2 _e/ e/ | dBB B2 c/B/ | AFF BGc | 
 AFF F2 z :|  