Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/4
M:5/4
K:Gmin
['B c']  
X:1
L:1/4
M:5/4
K:Gmin
 D | G A B c A | G/A/ G/F/ D2 d | d c A G E | G A/c/ B2 c |[M:6/4] d3/2 e/d/c/ B c d/e/ | 
 d B A3 c/>B/ |[M:5/4] G/F/ D F G A/c/ | c B !fermata!G2 z |]  