Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:6/8
K:G
['G3 G2 c B2 G (B/c/d)B', 'B>cd ded ded']  
X:1
L:1/8
M:6/8
K:G
 G3 G2 c | B2 G (B/c/d)B | G3 Bcd | EFG AFD | G3 G2 c | B2 G (B/c/d)B | gfe dcB | ABG FED :: 
 B>cd ded | ded dcB | c>de efe | efe edc | B>cd ded | ded def | gfe dcB | ABG FED :|  