Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:6/8
K:G
['c2 e', 'f2 d']  
X:1
L:1/8
M:6/8
K:G
 G>AG c2 e | d<dA c2 e | G>AG c2 d | ecA A2 c | G>AG c2 e | d<dA c2 e | g>fe f2 d | ecA A2{BA} G :: 
 gfe f2 d | edc f2 d | gfe f2 d | ecA A2 G | gfe f2 d | edc f2 d | G>AG f2 d | ecA A2{BA} G :|  