Construct a melodic piece using the designated alphabetic pattern and the provided musical theme.
X:1
L:1/4
M:2/4
K:G
['D2 d2 B B/A/ G2 F F/G/', 'B D']  
X:1
L:1/4
M:2/4
K:G
 D2 d2 | B B/A/ G2 | F F/G/ A F | G/F/G/A/ B G | D2 d2 | B B/A/ G2 | F F/G/ A F | G B G2 :: 
 D B D B | D d B G | D c A F | G/A/B/c/ d B | D B D B | D d B G | D c A F | G G/F/ G2 :|  