Construct a musical composition following the given alphabetical structure and incorporating the specified motif.
X:1
L:1/8
M:6/8
K:Bb
['f2 e']  
X:1
L:1/8
M:6/8
K:Bb
 f2 f f2 d | f2 e c3 | def e2 d | cdc B2 z | B2 c d2 B | Bcd e2 c | cde f2 e | d2 c B2 z | 
 B2 c d2 B | Bcd e2 c | cde f2 e | d2 c B2 z |]  