Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:3/4
K:Amin
['AA/B/ cc/B/ AB cd e2 ce eg', 'z2 eg gf df ag e2 c2']  
X:1
L:1/8
M:3/4
K:Amin
 AA/B/ cc/B/ AB | cd e2 ce | eg gf df | ag e2 z2 :: eg gf df | ag e2 c2 | cB/c/ d2 e2 | gf d2 B2 | 
 c/B/c/d/ ee cc | BB A2 z2 :|  