Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
M:6/8
K:G
['G3/2 F/ E']  
X:1
L:1/8
M:6/8
K:G
 B, | EEE ^D2 B, | GGG F2 A | G3/2 F/ E FE^D | E E2 z2 B,/B,/ | EEE ^D2 B,/B,/ | GGG F2 G/A/ | 
 G3/2 F/ E FE^D | E E2 z2 G/A/ | BBB B2 G | AAA A2 E/F/ | G2 E BAG | G F2 z2 B, | 
 E3/2 E/ E ^D2 B, | GGG F2 G/A/ | G3/2 F/ E F2 E/^D/ | E E2 z2 ||  