I know that this question has been asked in a different way: 

[MATLAB: Identify if a value is repeated sequentially N times in a vector](https://stackoverflow.com/questions/11494603/matlab-identify-if-a-value-is-repeated-sequentially-n-times-in-a-vector#)

I am wondering how I can exactly follow upper link if I am dealing with a matrix a coordinates, like: `M = [ x1 x2 x3 x4 ... xn; y1 y2 y3 y4 ... yn]`

for example n= 3 times:

```
M=  [ 2 3 3 3 1 4 4 4 6 6 6 6 8; 1 2 2 7 9 5 5 5 4 4 3 3 2]

ans: [ 4 4 4; 5 5 5] at position 6

```

I am looking for finding a column which has been repeated 3 times "sequentially".
In the mentioned link there is a way to do this for a vector.