Aligning sticky cubes

Hi!

I am trying to realize a Lego-like constructor. It will work with cubes with different materials. I made a prefab for a cube with this script: using UnityEngine; using System.Collections;

 [RequireComponent(typeof(BoxCollider))]
 [RequireComponent(typeof(Rigidbody))]
 public class StickScript : MonoBehaviour
 {
     private Rigidbody myRigid;    
     public void Start()
     {
 
         myRigid = gameObject.GetComponent<Rigidbody>();
     }
 
     public void OnCollisionEnter(Collision collision)
     {
         // all sticky objects have this tag
         if (collision.gameObject.tag != "Sticky")
             return;
 
         
         // if we are not connected to other object
         foreach (FixedJoint fj in collision.gameObject.GetComponents<FixedJoint>())
         {
             if (fj.connectedBody == myRigid)
                 return;
         }
 
         var otherRigid = collision.gameObject.GetComponent<Rigidbody>();
         
         // if we didn't connected other object
         foreach (FixedJoint fj in gameObject.GetComponents<FixedJoint>())
         {
             if (fj.connectedBody == otherRigid)
                 return;
         }
 
         // Connecting
 
         collision.gameObject.transform.rotation = gameObject.transform.rotation;  // rotating
         var joint = gameObject.AddComponent<FixedJoint>();
         joint.connectedBody = collision.rigidbody;
 
 
     }
 }

I am rotating the cubes, so they aligned properly... But i didn't understand how to make cubes to stick aligned: cubes must be connected by edges. Without this, I am getting this:

Can you help me with the position transformation when sticking?

With best regards

P. S. The mechanism of connecting: I am moving this blocks by using Leap Motion - they are rigidbodies, so I can move them by hands