Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/4
M:3/4
K:C
['B B']  
X:1
L:1/4
M:3/4
K:C
 D | B B B | B G G | d A A | A2 d | d e c | d e c | B c A | G G G | G2 ||  