Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/4
Q:1/4=90
M:3/4
K:G
['E2 B G3/2 A/ B', 'd2 d']  
X:1
L:1/4
Q:1/4=90
M:3/4
K:G
 B | E2 B | G3/2 A/ B | A2 G | F3/2 E/ ^D | E2 B | G3/2 A/ B | A G F | E2 :| B/c/ | d2 d | 
 d3/2 c/ B | A2 A | A B ^c | d2 d | d =c B | A B ^c | d2 d | B2 E | B3/2 A/ G | A2 G | F3/2 E/ ^D | 
 E2 B | G3/2 A/ B | A G F | E2 ||  