Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
Q:3/8=90
M:6/8
K:G
['EAA A2 G/A/', 'g/a/ |{ga} bag egd']  
X:1
L:1/8
Q:3/8=90
M:6/8
K:G
|: B/c/ | dBG BGD | EAA A2 G/A/ | BAG dBG | Bdd d2 c/B/ | cec dc/B/A/G/ | EAA A2 G/A/ | B>AG EGD | 
 EGG G2 :: g/a/ |{ga} bag egd | eaa a2 g/a/ |{ga} bag egd | egg g2 B | cec dBG | EAA A2 G/A/ | 
 BAG EGD | EGG G2 g/a/ |{ga} bag egd | eaa a2 g/a/ |{ga} bag egd | egg Tg2 B | 
 c/e/d/c/B/A/ B/d/c/B/A/G/ | EAA A2 G/A/ | dc/B/A/G/ GBD | EGG G2 :|  