Compose a piece using the alphabetic notation of the assigned musical structure and the provided melodic motif.
X:1
L:1/8
M:2/4
K:Bb
['B BAAc B3 d ecBA B2 z']  
X:1
L:1/8
M:2/4
K:Bb
 B | BAAc | B3 d | ecBA | B2 z d | dedc | cBAB | cdcB | A2 z A | A B2 d | d c2 e | d4 | c2 z c | 
 fdB_A | Gedc | B2 A2 | B2 z |]  