Create a musical composition based on the alphabetic representation of the predetermined pattern and the given melodic theme.
X:1
L:1/8
M:2/4
K:Bb
['(BAB)D EFGA', 'bf bf']  
X:1
L:1/8
M:2/4
K:Bb
 (BAB)D | EFGA | (BAB)D | EFGA | B2 bf | dB FD | C2 [AF]2 | [BD]2 z2 :: cAdB | eAdA | bf bf | 
 bf dB | [ec]AcA | eA cA | bf bf | b2 z2 :|  