Craft a piece of music that integrates both the suggested theme and letter-based structure.
X:1
L:1/8
M:6/8
K:G
['B2 B BAB d2 c AGF G2', 'g f2 d']  
X:1
L:1/8
M:6/8
K:G
 B2 B BAB | d2 c AGF | G2 G GFG | BAG A2 B | c2 c cBc | e2 d B2 c | ded cAF | G3 G2 :: g | 
 f2 d def | gfg a2 g | f2 d ded | c2 A A2 g | f2 d def | gfg a2 g |1 fed ed^c | d3 d2 :|2 
 fed ed^c | d3 d2 c ||  