Construct a melodic piece using the designated alphabetic pattern and the provided musical theme.
X:1
L:1/8
M:6/8
K:Dmix
['d2 B', 'def fgf']  
X:1
L:1/8
M:6/8
K:Dmix
 d2 B AFA | AFA Afe | d2 B AFD | EFE efe | d2 B AFA | AFA AGF | GAB AGF | EFE efe :: def fgf | 
 def f2 e | def fgf | efe g2 e | def fgf | fgf fgf | gab agf | efe f2 e :|  