How to flip every 5th row and column in matrix

For exaple I have

1 1 1

2 2 2

3 3 3

4 4 4

5 5 5

6 6 6

7 7 7

8 8 8

9 9 9

10 10 10

11 11 11

12 12 12

and I need to get

1 1 1

2 2 2

3 3 3

6 6 6

5 5 5

4 4 4

7 7 7

8 8 8

9 9 9

12 12 12

11 11 11

10 10 10

If I have matrix 12x3 and I divide it in 4 smaller matrix, I have to flip rows in every other matrix. I hope you got what I need.

[Dennis]

A=[1 1 1; 2 2 2; 3 3 3; 4 4 4; 5 5 5; 6 6 6; 7 7 7; 8 8 8; 9 9 9; 10 10 10; 11 11 11; 12 12 12];
for k=0:1
    A(k*6+4:k*6+6,1:3)=A(k*6+6:-1:k*6+4,1:3)
end

Answer 1

[Stephen23]

>> M = repmat((1:12).',1,3)
M =
    1    1    1
    2    2    2
    3    3    3
    4    4    4
    5    5    5
    6    6    6
    7    7    7
    8    8    8
    9    9    9
   10   10   10
   11   11   11
   12   12   12
>> M([4:6:end,6:6:end],:) = M([6:6:end,4:6:end],:)
M =
    1    1    1
    2    2    2
    3    3    3
    6    6    6
    5    5    5
    4    4    4
    7    7    7
    8    8    8
    9    9    9
   12   12   12
   11   11   11
   10   10   10