Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/4
M:3/4
K:Gmin
['A4 B2 A F G2 D2 c4']  
X:1
L:1/4
M:3/4
K:Gmin
 A4 | B2 A F | G2 D2 | c4 | A2 c2 | d4 | d e d B | c2 B A | G4 | D4 | G2 A2 | G F D C | D4 | F4 | 
 G4- | G4 |]  