Write a musical work incorporating the specified theme and letter-based framework.
X:1
L:1/8
M:9/8
K:G
['dBG GAG BAG', 'def gag fed']  
X:1
L:1/8
M:9/8
K:G
 dBG GAG BAG | dBG GBd e2 g | dBG GAG BAG | e2 A ABA c2 e :: def gag fed | g2 B B2 c d2 B | 
 def gag fed | a2 A A2 B c2 e :|  