Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:2/4
K:C
['.[GDB,]2 .[GDB,]2 .[GDB,] .[GDB,]', 'G4- G4 G2 G>G A G2 F', 'G3 z cG G2', 'D2 CF ED C3']  
X:1
L:1/8
M:2/4
K:C
|:"G7" .[GDB,]2 | .[GDB,]2 | .[GDB,] .[GDB,] | .[GDB,]2 :|"G7" G4- | G4 ||"C" G2 G>G |"G7" A G2 F | 
"C" EE DC |"G7" G3 z || |"C" GG GG |"G7" A G2 F |"C" EE"G7" DD |"C" C3 z ||"C" EG C2 | EG C2 | 
"F" A>A AA |"C" G3 z || |"C" cG G2 |"Dm" FE D2 |"G7" CF ED |"C" G3 z |"C" cG G2 |"Dm" FE D2 | 
"G7" CF ED |"C" C3 z :|  