Construct a melodic piece using the designated alphabetic pattern and the provided musical theme.
X:1
L:1/8
M:6/8
K:G
['Bcd Bcd B2 G G2', 'd gfg']  
X:1
L:1/8
M:6/8
K:G
 d | Bcd Bcd | B2 G G2 d | efg efg | f2 d d2 c | Bcd Bcd | B2 G G2 B | A2 B ^c2 A | (d3 d2) :: d | 
 gfg de=f | e2 c c2 e | a^ga ef=g | f2 d d2 d | gfg dBd | e^de cAc | d^cd DEF | (G3 G2) :|  