Create a circle using cubes?

Ok, using two for loops one can create a a grid of cubes, just instantiate a cube increasingly on the x and y axis. How would one do this to create a circle or a ring?

Thanks guys in advanced!

Thanks guys, found the answer though. I just derived the x and y values from cosine and sin.

public GameObject cube;


	void Start()
	{
		int x, y;
		int length = 50;
		float angle = 0.0f;
		float interval = 0.1f;

		while (angle < 2 * Mathf.PI)
		{
			x = (int)(length * Mathf.Cos (angle));
			y = (int)(length * Mathf.Sin (angle));
			Instantiate(cube,new Vector3(x,y,0),Quaternion.identity);
			angle += interval;
		}
	}

what if i want it to be spawned internally rather than just creating a border? @SnotE101

For people who are trying to do this in 3D space , you just have to do is to change y to z
so code will be something like this

public GameObject cube;

 void Start()
 {
     int x, z;
     int length = 50;
     float angle = 0.0f;
     float interval = 0.1f;

     while (angle < 2 * Mathf.PI)
     {
         x = (int)(length * Mathf.Cos (angle));
         z = (int)(length * Mathf.Sin (angle));
         Instantiate(cube,new Vector3(x,0,z),Quaternion.identity);
         angle += interval;
     }

base code by SnotE101