Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
Q:3/8=88
M:6/8
K:G
['G2 B']  
X:1
L:1/8
Q:3/8=88
M:6/8
K:G
 G2 B | A>GF G2 B | A3 B2 c | c>BA B2 A | G3 A2 G | B>BA G2 B | F3 B2 B | c>BA B2 A | G2 z ||  