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
['dBAc BG G2', 'agef g2 gf']  
X:1
L:1/8
M:4/4
K:G
 ge | dBAc B G2 A | B2 BA Bdge | dBAc BG G2 | eaag ageg | dBAc BG G2 | DBBA Bdge | dBAc BG G2 | 
 eaag agef || g2 gf gaba | g2 gb agef | g2 gf ga(3bag | eaag agef | g2 gf gaba | g2 gb a2 ga | 
 (3bag af gfed | eaag a2 ||  