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
['efg fdd def afd dBG cAd BGG']  
X:1
L:1/8
M:6/8
K:G
"^A" d |"G" GBd gfg |"C" edc"D7" BcA |"G" GBd"A7" efg |"D7" fdd def |"G" gbg"D" afd | 
"C" cde"G" dBG |"Em" GAB"D7" cAd |"G" BGG G2 :|"^B" G/A/ |"G" BGB"C" c2 e |"G" dBG"D7" A2 G | 
"G" GBd"A7" efg |"D7" fdd def |"G" gbg"D" afd |"C" cde"G" dBG |"Em" GAB"D7" cAd |"G" BGG G2 :|  