You need to understand that
will be getting the length of the *STRINGS* "m1", "m2", etc.
And EACH of those strings is indeed only 2 character long.
So that's why you were getting only 2 elements per subarray.
I don't know why you thought
would magically turn into one of your arrays. Just because a string contains the *NAME* of an array does not make it the same as the array.