Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:6/8
K:D
['A2 A A2 B']  
X:1
L:1/8
M:6/8
K:D
|:"D" A2 A A2 B |"A7" FGE"D" DFG |"D" ABA AFA |"G" B3"D" d3 |"D" A2 A A2 B |"Em" G2 F"A7" E2 D | 
"G" dcB"D" AFA |"G" B3"D" d3 ::"D" d2 e"Bm" f2 g |"Em" efd"A7" ecA |"D" d2 e"Bm" fgf | 
"Em" e3"A7" A3 |"D" d2 e"Bm" fgf |"E" efd"A7" ecA |"G" (B{c}d)B"D" AFA |"G" B3"D" d3 :|  