Compose a piece of music using the specified letter-based musical form and incorporating the assigned motif.
X:1
L:1/4
M:4/4
K:G
['_B A']  
X:1
L:1/4
M:4/4
K:G
 G | G d/d/ d c/_e/ | d _B A B/A/ | G F/G/ c c/_B/ | A2 z _B | A A/A/ A F/D/ | G _B A d | 
 c _B/B/ A B | G2 z |]  