Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/16
Q:1/4=140
M:2/2
K:C
['e4 g4', 'defe d2', 'g2a2 g4', 'd4 e2c2B2c2 dcdfe2 c2 e2c2B2c2', 'd2e2 c4 dedcB2 G2 f2e2d2>g2 ^f2 ag']  
X:1
L:1/16
Q:1/4=140
M:2/2
K:C
"^A" e4 g4 defd e2c2 | e4 g4 de d2 c4 :: defe d2 ef g2 f2 e2 c2 | defe d2 ed c2 B2 c4 :: 
"^B" g2a2 g4 fgfe d4 | g2a2 g4 fgfe d4 :: e2c2B2c2 dcdfe2 c2 | e2c2B2c2 dedB c4 :: 
"^C" d2e2 c4 dedcB2 G2 | f2e2d2>g2 ^f2 ag e4 | d2e2 c4 dedcB2 G2 | f2e2d2>g2 ^f2 ag c4 | 
 efge c2 e2e2 dc d4 | defd B2 d2cBce g4 | efge c2 e2e2 dc d4 | defd B2 d2cBce c4 |]  