[SOLVED] Only instantiating once

So, I have some code that I am trying to use to create a line over the top of another line (a gameobject), however, that line underneath is made from a prefab. I have the original prefab to the side, but whenever I try to instantiate a line, it only works once, even though I can click on different ones, and also it only pastes it over the prefab to the side. Any ideas?

Code:

 var newSkin : GUISkin;
 var redLine : GameObject;
 var blueLine : GameObject;
 var x : int;
 var y : int;
 var usable : boolean;
 var cube : GameObject;
 var isHit : boolean;
 
 function Start() {
     x = transform.position.x;
     y = transform.position.y;
     usable = true;
 }
 
 function Update() {
     lineButton();
     if (Input.GetMouseButton(0)) {
         var hit : RaycastHit;
         var ray = Camera.main.ScreenPointToRay (Input.mousePosition);
         if (Physics.Raycast (ray, hit)) {
             if (hit.collider.gameObject.tag==gameObject.collider)
             {
                 isHit = true;
             }
             else
             {
                 isHit = false;
             }
         }
     }
     lineButton();
 }
 
 function lineButton() {
     if(!VarDefiner.isMainMenu)
     {
         if(isHit && usable)
         {
             if(VarDefiner.redTurn)
             {
                 cube = Instantiate(redLine, new Vector3(transform.position.x, transform.position.y, 15), Quaternion.Euler(transform.rotation.x, transform.rotation.y, transform.rotation.z + 89.2929));
                 usable = false;
                 isHit = false;
                 VarDefiner.redTurn = false;
             }
             else
             {
                 cube = Instantiate(blueLine, new Vector3(x - 0.5, y + 0.35, 15), Quaternion.Euler(transform.rotation.x, transform.rotation.y, transform.rotation.z + 89.2929));
                 usable = false;
                 isHit = false;
                 VarDefiner.redTurn = true;
             }
         }
     }
 }