Making random tiles

Hey guys,

simple question with probably a simple answer here, but still difficult enough for me to not find anything about how to solve it…
I want to make a grid of tiles in random colors, picked out of 7 preset colors. So I made a script for it, attached it to the tile gameobject, but… the field of tiles always has the same random color (like every tile blue, or red), not every tile a different color as I want it to…
How do I solve this? I’m sure there must be some easy solution for it, not having to make a different script and different material for every tile? So how do I make the script run again for every tile prefab in the field and not just once for the main tile?
I’m working with C#.

Don’t know how your script looks like (hint), but my first try would be something like this (JS):

function Start() {
    var ranNmbr = Random.Range(0, 6);
    switch(ranNmbr) {
        case 0 : transform.renderer.material.color = Color.red;
        break;    

        case 1 : transform.renderer.material.color = Color.blue;
        break;       

        case 2 : transform.renderer.material.color = Color.green;
        break;    

        case 3 : transform.renderer.material.color = Color.yellow;
        break;  

        case 4 : transform.renderer.material.color = Color.cyan;
        break;    

        case 5 : transform.renderer.material.color = Color.magenta;
        break;       
    }
}