How to random Different Value - My code error or Bug ??

This script for randoming multiple prefab ^ i have double this code and get 2 multiple prefab randomly at same time but here my problem :
1- the 1st is problem on my result is sometimes get 2 same value in random (How to get 2 a different random prefab at same times ^ random A-Random B , A not same value B)
2- The result Sometimes fixed in horizontal angle but sometimes 2 value image fused and sometimes in Vertical position (How to get Fixed colider image in horizontal line )
-Screen shot on Bottom-
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Code (csharp):

1.  
2. using UnityEngine;
3. using System.Collections;
4.  
5. public class SpawnMultipleOBJ_angka : MonoBehaviour {
6.  
7.     private Vector3 startPosition;
8.     private float newXPos = 0f;
9.  
10.     public float moveSpeed = 1f;
11.     public float moveDistance = 4f;
12.  
13.  
14.     //initiate aray
15.     public GameObject[] gameObjectSet;
16.  
17.     public float timeLeftUntilSpawn = 0f;
18.     public float startTime = 0f;
19.  
20.     public float secondsBetweenSpawn = 3f;
21.  
22.     // Use this for initialization
23.     void Start () {
24.         startPosition = transform.position;
25.     }
26.     void SpawnRandomObject(){
27.         int whichItem = Random.Range (0, 9);
28.         //Debug.Log ("Our Random number is " + whichItem);
29.         GameObject myObj = Instantiate (gameObjectSet [whichItem])as GameObject;
30.  
31.         myObj.transform.position = transform.position;
32.     }
33.  
34.     // Update is called once per frame
35.     void Update () {
36.     //Move Distant
37.         newXPos = Mathf.PingPong (Time.time * moveSpeed, moveDistance) - (moveDistance / 2f);
38.         transform.position = new Vector3 (newXPos, startPosition.y, startPosition.z);
39.         timeLeftUntilSpawn = Time.time - startTime;
40.  
41.         if (timeLeftUntilSpawn >= secondsBetweenSpawn){
42.             startTime = Time.time;
43.             timeLeftUntilSpawn = 1;
44.  
45.                 SpawnRandomObject();
46.         }
47.     }
48. }
49.  

 

[ code] [/ code] tags when you paste code into the forums please, it really helps with readability, there is a sticky at the top of the scripting forum on them...

 

Like this

Code (csharp):

1.  
2. using UnityEngine;
3. using System.Collections;
4.  
5. public class SpawnMultipleOBJ_angka : MonoBehaviour {
6.  
7. private Vector3 startPosition;
8. private float newXPos = 0f;
9.  
10. public float moveSpeed = 1f;
11. public float moveDistance = 4f;
12.  
13.  
14. //initiate aray
15. public GameObject[] gameObjectSet;
16.  
17. public float timeLeftUntilSpawn = 0f;
18. public float startTime = 0f;
19.  
20. public float secondsBetweenSpawn = 3f;
21.  
22. // Use this for initialization
23. void Start () {
24. startPosition = transform.position;
25. }
26. void SpawnRandomObject(){
27. int whichItem = Random.Range (0, 9);
28. //Debug.Log ("Our Random number is " + whichItem);
29. GameObject myObj = Instantiate (gameObjectSet [whichItem])as GameObject;
30.  
31. myObj.transform.position = transform.position;
32. }
33.  
34. // Update is called once per frame
35. void Update () {
36. //Move Distant
37. newXPos = Mathf.PingPong (Time.time * moveSpeed, moveDistance) - (moveDistance / 2f);
38. transform.position = new Vector3 (newXPos, startPosition.y, startPosition.z);
39. timeLeftUntilSpawn = Time.time - startTime;
40.  
41. if (timeLeftUntilSpawn >= secondsBetweenSpawn){
42. startTime = Time.time;
43. timeLeftUntilSpawn = 1;
44.  
45. SpawnRandomObject();
46. }
47. }
48. }
49. [/core]