Example 1:
A = {1,2}, B = {a,b,c}
Cartesian Product:
{(1,a), (1,b), (1,c), (2,a), (2,b), (2,c)}
Example 2:
A = {1,2}, B = {a,b}, C = {x,y}
{(1,a,x), (1,a,y), (1,b,x), (1,b,y), (2,a,x), (2,a,y), (2,b,x), (2,b,y)}