Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:2/2
K:D
['F2 A2', 'c2 (BA)']  
X:1
L:1/8
M:2/2
K:D
 AG | F2 E>D F2 A2 | d3 e c2 (BA) | B2 A>F (dB) (AF) | E3 F (EF)(GA) | F2 (ED) F2 A2 | d4 A4 | 
 (Bc) d2 d3 c | d6 :| (fg) |{g} e2 d>e c2 (BA) | d4 A2 (de) | (fe) (dB) (AF) (ED) | E6 AG | 
 F2 D2 F2 A2 | d3 e c2 (BA) | (Bc)(dB) (cd)(ef) | d6 |]  