Infinite scrolling background

try to adapt this code to your neededs, create a new scene, add a cube, set the cube scale.x to 2 and scale.z to 2 too put the script on the camera, asign the object variable with your created cube and have fun!

 #pragma strict
 var objectprefab : GameObject;
 var whatIhavehere : GameObject[];
 var objectscalez : float = 2;
 var objectscalex : float = 2;
 var numberofobjects : int;
 var zoffset : float = 2;
 var yoffset : float = -2;
 var z : int;
 var proxblock : int;
 var centerx : float; 
 function Start () {
 
 numberofobjects = 5; 
 whatIhavehere = new GameObject[numberofobjects*10];
 
 transform.position.z += 3*Time.deltaTime;
 z =Mathf.FloorToInt(transform.position.z);
 proxblock = z+numberofobjects;
  centerx = transform.position.x;
 }
  
  
 function Update () 
 {
  
 // transform a float position in a int position,
 z =Mathf.FloorToInt(transform.position.z);
 if(z+(numberofobjects) == proxblock)
 {
 var posi : Vector3;
 posi = Vector3( centerx,transform.position.y+yoffset,z+(numberofobjects*objectscalez)+zoffset);
     whatIhavehere[foundone()] =Instantiate(objectprefab,posi,objectprefab.transform.rotation);
     whatIhavehere[foundone()] =Instantiate(objectprefab,posi-Vector3(objectscalex,0,0),objectprefab.transform.rotation);
     whatIhavehere[foundone()] =Instantiate(objectprefab,posi+Vector3(objectscalex,0,0),objectprefab.transform.rotation);
     proxblock += objectscalez;
 }
 
        if(Input.GetKeyDown ("a")&& transform.position.x >= centerx )
        {
        moveTo(transform.position.x - 1.5, 20); //Feed the moveTo() function the X/Y positions you want it to move to, and the Speed you want it to move at
        }
 
        if(Input.GetKeyDown ("d")&& transform.position.x <= centerx )
        {
        moveTo(transform.position.x + 1.5, 20); //Feed the moveTo() function the X/Y positions you want it to move to, and the Speed you want it to move at
        }
       
  transform.position.z += 3.0*Time.deltaTime;      
 }
  
 function moveTo(posX : float, speed : float)
 {
     while(posX!= transform.position.x)
        {
          transform.position = Vector3.MoveTowards (transform.position,new Vector3(posX,transform.position.y,transform.position.z),speed * Time.deltaTime);
          yield;
        }
 
 }
  
 function foundone () 
 {
     for(var i=0;i<whatIhavehere.Length;i++)
     {
        if(whatIhavehere[i] == null)
          return(i);
        else
        {
          if((whatIhavehere[i].transform.position.z -z)<z-proxblock)
          {
           Destroy(whatIhavehere[i]);
           return(i);
          }
        }
     }
     return(i);
 }