Create music using the given musical theme and adhere to the outlined letter-based structure.
X:1
L:1/8
M:2/4
K:G
['A/B/ dB AG AG AB', 'd2 g3 a/b/ g2']  
X:1
L:1/8
M:2/4
K:G
 D2 | B3"^a." A/B/ | dB AG | AG AB | cB AG | B3"^a." A/B/ | dB AG | AG AB | G2 G>G | G2 :: d2 | 
 g3 a/b/ | g2 d2 | g3 a/b/ | g2 G2 | AG AB | G2 G>G | G2 :|"^Var:""^a." B |]  