Appending to multidimensional dynamic array

[kerdemdemir via Digitalmars-d-learn]

I want to append a 2D array to my 3D array. I expect it should be 
same as int[] arr; arr ~= 3;

void readInput()
{
    char[][][] candidate;
    char[] buff;
    size_t counter = 0;
    while (  stdin.readln(buff) )
    {
        char[][] line = buff.chomp().split();
        writeln(line);
        candidate ~= line;
        writeln(candidate);
        if (++counter > 1 ) break;
    }
}

And I send the inputs below

201212?4 64
20121235 93
I expect a output like

[["201212?4", "64"], ["20121235", "93"]]
But instead I see

[["20121235", "93"], ["20121235", "93"]]

In short :
=~ replaces all the elements in the array with the last added. 
Where am I doing wrong? How can I meet my expectation?


By the way I am posting the same question to stackoverflow at the 
same time. Does sending questions to stackoverflow as well as 
here not desirable for D community? If so I will just write here.