Best way to make these tree iterations? Arrays? tags? nested etc

Hi there, i am learning nested functions in javascript and Unity3d.

I am stuck on this task: rotate a root object 3 times, add 10 cubes in a line to the root object, mark the 10th cube as a new root object, rotate the new root object 3 times, add 30 cubes to the new root object same as before.

I am very stuck on this task: how to i mark the 3 new cubes at the end of each branch as a sub root, seeing as they wont have existed before the rotate function was made in the first place? do i tag them and find them at the end of the first run of lines? Should i make an array with "newroot [1,2,3]" where do i place the nested elements of the function?

here is the code for the 3 branches.: #pragma strict

 @script RequireComponent(AudioSource)
 
 var cubePrefab : GameObject ;//set cube for model
 var startObj : GameObject ;
 startObj = gameObject ;//set root object of function
 private var rot : Quaternion; //set empty rotation var
 rot.eulerAngles = Vector3(0, 0, 0);
 
 
 function Start()//running this triggers all sub functions
 {    
     Rotate (startObj,rot);
 }
 
 function Rotate (ting:GameObject,trot:Quaternion)//rotate the root object 3 times
 {    
     for (var x = 0; x < 3; x++)
     {    
         trot.eulerAngles = Vector3(0,120,0);
         ting.transform.rotation = ting.transform.rotation * trot;//take base point and add TROT degrees every loop
         Lines( ting, 1.0  , 10.0);//add 10 cubes in a line to the root object
     }
 }
 
 function Lines( iter:GameObject, ratio:float , depth:float)//add line of cubes
 
 {
 
     var cube = Instantiate(cubePrefab,Vector3(0, 0, 0),rot);
     var turn = Vector3(0, 4, 3);
     rot.eulerAngles = turn;
        
     cube.transform.position = iter.transform.TransformPoint(Vector3(1, 0, 0));//places new cube on top of last one's relative position
     cube.transform.localScale = Vector3(2,2,2);
     cube.transform.localScale *= ratio;
     //cube.transform.localScale *=.90;//sets size of old cube to new one
     cube.transform.rotation = iter.transform.rotation * rot;
     //print (iter.transform.rotation);
     if(depth > 0)
     {
         Lines( cube, ratio *.98 , depth -1 );            
     }                
 }