2d isometric tile-based game system help?

Hi there,

I am working on a 2d tile based system with a 3d camera set at a 45 degree angle to look isometric. I have the following code working which will generate the level.

 some Code
 var blockPiece:GameObject[]; // fill this
 var debugMat:Material;
 var pieces: GameObject[ , ];

 var width = 20;
 var length = 20;

 private var levelArray:int[] = [7,0,7,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                                 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                                 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                                 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                                 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                                 0,0,0,0,0,0,0,0,1,1,1,0,0,0,0,0,0,0,0,0,
                                 0,0,0,0,0,0,1,1,1,1,1,1,1,1,0,0,0,0,0,0,
                                 0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,
                                 0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,
                                 0,0,0,0,1,1,1,1,1,1,6,6,1,1,1,1,0,0,0,0,
                                 0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,
                                 0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,
                                 0,0,0,0,0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,
                                 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                                 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                                 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                                 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                                 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                                 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                                 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0];
 function Awake() {
     generateTiles();
 }

 function generateTiles(){
 pieces = new GameObject[width, length]; // creates the object array
   
 for(z=0; z<length; z++){
   for(x=0; x<width; x++){
         
     var prefab: GameObject;
     
     // Set pefab to be inLibrary prefab based on level array
     prefab = blockPiece[levelArray[z*width + x]];
     
     // Add piece to stage
     pieces[x,z] = Instantiate (prefab, Vector3(x,1,(z*-1)), Quaternion.Euler(0, 180,   0));
     //pieces[x, z].renderer.material = debugMat;
     
        }
     }
 }

 function Start(){
     // Do rotateBlocks function
 }

Everything works in terms of generating the level, feel free to use the code if you like.

My problem is that I don't know where to go from here. How do I set certain pieces to be corners?. I also can't seem to find a good way to access and know a blocks type for running other commands. Any ideas?