Compose a musical piece using the designated musical pattern's alphabetic representation and the assigned melodic theme.
X:1
L:1/8
M:4/4
K:G
['BcdB G2 AB', 'fd g2']  
X:1
L:1/8
M:4/4
K:G
|: (3Bcd | g2 bg d2 gd | BcdB G2 AB | cded cBAG | F/G/AEF D2 (3def | g2 bg dggd | BcdB G2 AB | 
 cedc BAGF | A2 GF G2 :: Bc | d2 dB g2 gf | ecec a2 ag | f2 fd g2 ge | fgaf d2 fd | g2 bg d2 gd | 
 BcdB G2 AB | cedc BAGF | A2 GF G2 :|  