Compose a musical piece using the designated musical pattern's alphabetic representation and the assigned melodic theme.
X:1
L:1/8
M:6/8
K:A
['ecA AGA', 'eca eca']  
X:1
L:1/8
M:6/8
K:A
 (c/d/) | ecA AGA | ecA AGA | FdB Ged | cBA BGE | ecA AGA | ecA AGA | FdB Ged | cAA A2 :: 
 (A/4B/4c/4d/4) | eca eca | eca edc | fdB BbB | BB,B B2 (A/4B/4c/4d/4) | eca eca | eca ecA | 
 EAc eca | B>AB A2 :|  