Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:2/2
K:A
['ecAB c3 d edce dBGB', 'eaag efge dBge dBGB']  
X:1
L:1/8
M:2/2
K:A
 (cd) | ecAB c3 d | edce dBGB | AGAB cBcd | efge afgf | ecAB c3 d | edce dBGB | AGAf gfgf | 
 edcB A2 |] (cd) | eaag efge | dBge dBGB | AGAB cBcd | e^def gfed | eaag efge | dBge dBGB | 
 ABcd efge | dBGB A2 |]  