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:G
['', 'd B3 d2']  
X:1
L:1/8
M:4/4
K:G
 d2 Bd |: egdB G3 B | D G3 DG B2 | dBAB G3 A | Beed e2 ge | dBAB G3 B | D G3 DG B2 | dBAB G3 A | 
 Beed e2 ge | d B3 d2 ge | d B3 d2 ge | d2 Bd g3 d | egdB A3 B | d B3 d2 gf | edef g3 a | 
 b2 af gfed | egfa g2 z d :|  