Craft a musical piece that integrates the provided melodic theme and the corresponding alphabetical pattern.
X:1
L:1/4
M:4/4
K:G
['G B']  
X:1
L:1/4
M:4/4
K:G
 z2 D2 | G B G D | G B G D | G B z2 | G B z2 | d d c B | A A F D | F A B3/2 B/ | A G z2 |]  