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
['(fe) d2 A2 B2 (AF) (AB)(de) (fe)(dB)', '(fe)(dB) (AF)(EF)']  
X:1
L:1/8
M:4/4
K:D
 (fe) | d2 A2 B2 (AF) | (AB)(de) (fe)(dB) | (AF)(EF) D2 D2 | D6 || (DE) | F2 A2 d2 (ef) | 
 g2 f2 e2 (de) | (fe)(dB) (AF)(EF) | A6 (DE) | F2 A2 d2 (ef) | g2 f2 e2 (de) | (fe)(dB) (AF)(EF) | 
 A6 (fe) | d2 A2 B2 (AF) | (AB)(de) (fe)(dB) | (AF)(EF) D2 D2 | D6 ||  