Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:6/8
K:C
['cBc dcB cGE CEG FEF', 'cBc g^fg ea^f']  
X:1
L:1/8
M:6/8
K:C
|: cBc dcB | cGE CEG | FEF DEF | GAB ced | cBc dcB | cGE CEG | FEF DGF | EC{D}C C3 :: cBc g^fg | 
 ea^f gec | A2 f fef | Adf afd | cBc g^fg | ea^f g2 a | gec fdB | cGE C3 :|  