Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:4/4
K:G
['', 'D2 B,D', 'BGAB cA (3AAA FAFA DFAB cAFA BG']  
X:1
L:1/8
M:4/4
K:G
 G2 GE |: D2 B,D G,DB,D | GEDB, DDGA | BBBA GABG | AGFA GFEF | GDGE D2 B,D | GEDB, D2 GA |1 
 BcBA BAGB | AGFA G2 GE :|2 B2 BA GABG | AGFA GFGA || BG (3GGG DGDG | B,DGA BGAB | cA (3AAA FAFA | 
 DFAB cAFA | BG (3GGG DGDG | B,DGA BGAB | cAFA BGDG |1 AFDF GFGA :|2 AFDF G2 GE ||  