Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:4/4
K:D
['DEFA d2 fd gdfd ed (3Bcd AdcA', 'fddd fdad']  
X:1
L:1/8
M:4/4
K:D
|: EDCE DEFA | d2 fd gdfd | ed (3Bcd AdcA | (3Bcd AF EGFD | E3 F DEFA | d2 fd gdfd | 
 ed (3Bcd AdcA | (3Bcd AGFD D2 :: fddd fdad | fddd ec A2 | fddd fdad | ceag fd d2 | fggf gfec | 
 cBAF G2 FG | AA^GB ABde | (3fga ea fd d2 :|  