how to insert a new column to a matrix after its every two column?

Hi; I have a matrix as:

A=

     1     1     1     1     1     1     
     5     1     5     1     3     1     
     4     2     4     2     2     2     
     2     2     3     3     4     2     
     3     3     2     3     5     2     
     7     3     6     4     6     3

and b is like:

1 2 3

3 3 2

1 1 3

5 6 1

1 2 1

5 1 5

I want to add every b's column to A's after every two column and I want to get:

new=

     1     1      1      1     1     2      1     1     3
     5     1      3      5     1     3      3     1     2
     4     2      1      4     2     1      2     2     3
     2     2      5      3     3     6      4     2     1
     3     3      1      2     3     2      5     2     1
     7     3      5      6     4     1      6     3     5

Thanks in advance;

Regards..

Answer 1

[Guillaume]

A more generic version of Stephen's method 1:

skipcolumns = 2;
bcols = (1:size(b, 2)) * (skipcolumns+1);
assert(size(b, 2) * skipcolumns == size(A, 2), 'number of columns in A and b don''t match skipcolumns');
acols = setdiff(1:size(b, 2)+size(A, 2), bcols);
new1(:, bcols) = b;
new1(:, acols) = A;

a more generic version of method 2:

skipcolumns = 2;
assert(size(b, 2) * skipcolumns == size(A, 2), 'number of columns in A and b don''t match skipcolumns');
new2 = reshape([reshape(A, size(A, 1)*skipcolumns, []); b], size(A, 1), [])

[bilgesu ak]

Thank you Guillaume very much. I applied method 2 and it is working...

Really this answer was perfect...

Regards..