Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/16
Q:1/4=100
M:2/4
K:D
['FGEF D2de fedc BcdB A2dF GFED', 'D2 ed cABc dfed cABc d2>F2 G2BA']  
X:1
L:1/16
Q:1/4=100
M:2/4
K:D
 AG | FGEF D2de | fedc BcdB | A2dF GFED | CEDF E2AG | FGEF D2de | fedc BcdB | A2dF GFED | 
 A,DCE D2 :: ed | cABc dfed | cABc d2>F2 | G2BA GFED | CEDF E2AG | FDGE AGFA | def^g a2fa | 
 gfed cABc | d2f2d2 :|  