Write a musical work incorporating the specified theme and letter-based framework.
X:1
L:1/8
M:6/8
K:G
['BAG BAA BAG', 'B2 z/']  
X:1
L:1/8
M:6/8
K:G
 BAG BAA | BAG ged | BAG BAA | BAG e2 e :| B2 z/ g/ B2 z/ a/ | e2 z/ g/{g} fed | 
 B2 z/ g/ B2 z/ a/ | e2 z/ g/ e2 z/ d/ | B2 g/ z/ B2 a/ z/ | e2 g/ z/{g} fed | B2 g/ z/ B2 a/ z/ | 
 e2 g/ z/ e2 d/ z/ ||  