How to reshape matrix in this way?

When reshape a 3D matrix into 2D matrix, it fills columns first; for example:

a(3,3,4) =

    1 1 1
    1 1 1
    1 1 1

    2 2 2
    2 2 2
    2 2 2

    3 3 3
    3 3 3
    3 3 3

    4 4 4
    4 4 4
    4 4 4

reshape(a,6,6) gives:

d =

     1     1     2     3     3     4
     1     1     2     3     3     4
     1     1     2     3     3     4
     1     2     2     3     4     4
     1     2     2     3     4     4
     1     2     2     3     4     4

How can it be reshaped to:

d =

     1     1     1     3     3     3
     1     1     1     3     3     3
     1     1     1     3     3     3
     2     2     2     4     4     4
     2     2     2     4     4     4
     2     2     2     4     4     4

or

d =

     1     1     1     2     2     2
     1     1     1     2     2     2
     1     1     1     2     2     2
     3     3     3     4     4     4
     3     3     3     4     4     4
     3     3     3     4     4     4

Thanks.

Answer 1

[Roger Stafford]

I think this does it for the first of your desired d's:

   d = reshape(permute(reshape(a,3,3,2,2),[1,3,2,4]),6,6);

Added:

The second desired d should be obtained with:

   d = reshape(permute(reshape(a,3,3,2,2),[1,4,2,3]),6,6);