Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
Q:1/4=80
M:2/4
K:G
['cB AG']  
X:1
L:1/8
Q:1/4=80
M:2/4
K:G
"G" g2 ed |"Am" cB AG |"C" e2 G2 |"D" F2 ED |"G" GB dB |"A7" A^c eg |"D" fd"A7" e^c |"D" d2 D2 | 
"G" g2 ed |"Am" cB AG |"C" e2 G2 |"D" F2 ED |"C" EG cE |"D7" DF Ac |"G" BA"D7" GF |"G" G2 G,2 || 
"G" Bd gf |"C" e2 dc |"G" Bd gf |"C" e2 dc |"G" Bd gf |"C" fe"G" ed |"C" dc B/c/d |"D" B2"D7" A2 | 
"C" cB AG |"D" F/G/A D2 |"C" cB AG |"Am7" e/f/g"D" f2 |"C" eG ge |"G" dB AG |"D" D2"D7" F2 | 
"G" G4 |]  