Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:9/8
K:Bmin
['F3 FEF', 'ecA ABc']  
X:1
L:1/8
M:9/8
K:Bmin
 F3 FEF c2 A | F3 FEF AFE | F3 FEF c2 d | ecA BAF AFE :| ecA ABc d2 f | ecA ABc BAF | 
 ecA ABc d2 B | cBA BAF AFE :|  