Generating a grid of cubes with space between.

Considering this is the first google answer that relates to this question, I figured it's worth answering properly.

Here is some example code to get a space between your grid items!

The magic happens on this line: newRoom.transform.position = new Vector3(x size.x, z size.x, y * size.x);

What we're doing is multiplying our grid item [Read: Cube]'s position by an incremented value. In other words, we're adding a number to the position that increases each time we add a cube.

size.x (in this case) could be anything that gets incremented during the for loop.

Feel free to paste this into the start function/method of a new script and play around with it. I've added the random generation of colors for the cubes to make things more visual.

 Vector3 size = new Vector3 (5,5,1);    //This is the size of our cube-grid. (5x5x1)    
 
 for (int x = 0; x < size.x; x++)
             {
             for (int y = 0; y < size.y; y++)
                 {
                 for (int z = 0; z < size.z; z++)
                     {
                     GameObject newRoom = GameObject.CreatePrimitive(PrimitiveType.Cube);
                     newRoom.name = (x > y) ? "x" + x : "y" + y;
                     newRoom.transform.position = new Vector3(x * size.x, z * size.x, y * size.x);
                     newRoom.GetComponent<Renderer>().material.color = new Color(Random.Range(0.0f, 1.0f), Random.Range(0.0f, 1.0f), Random.Range(0.0f, 1.0f));
                     newRoom.GetComponent<MeshRenderer>().shadowCastingMode = UnityEngine.Rendering.ShadowCastingMode.Off;
                     newRoom.transform.SetParent(transform);
                     }
                 }
             }
         }

using for statements within each other with an instantiation at the end... you should be able to come up with the rest...

or at least start making your own code instead of asking others to make your game for you