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:Emin
['', 'G3 A B2', 'B e3']  
X:1
L:1/8
M:4/4
K:Emin
 GA |: BGFG E3 F | Ggfg edBA | G3 A B2 EF | GEED EBAB | G3 A B2 GA | Bgfg efga | bgag egfg | 
 ecAF G3 A :: Bdef g3 a | bagf edBA | B e3 GAB^c | d2 ^ce d2 ef | gbaf gfed | BdAd B e3 | 
 GBAG FGA=c | BGAF G3 A :|  