Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/8
M:2/4
K:F
['(3C/D/E/ FF/F/ FA cA FA']  
X:1
L:1/8
M:2/4
K:F
 (3C/D/E/ | FF/F/ FA | cA FA | Gc/d/ cBAG | (A2 F) (3C/D/E/ | FF/F/ FA | cA FA | Gc de | f z F |]  