Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/4
M:4/4
K:G
['A B B B/c/d/e/ c A A', 'g/f/ e d']  
X:1
L:1/4
M:4/4
K:G
|:"^A" A | B B B/c/d/e/ | c A A B/c/ | d d d/c/B/A/ | B G G ::"^B" g/f/ | e d d G/A/ | B B B g/f/ | 
 e d c B | A G G :|  