Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
M:9/8
K:Dmix
['A/B/A A2 G', 'A2 D']  
X:1
L:1/8
M:9/8
K:Dmix
 A/B/A A2 G A2 D | A/B/A A2 G B2 d | A/B/A A2 G A2 c | B2 G G2 A B2 d :: A2 D D/D/D A2 D | 
 A2 D D/D/D B2 d | A2 D D/D/D A2 c | B2 G G2 A B2 d :|  