Flappy bird sort of game pipes goin crazy

Like you see in this video

The bottom pipes go crazy this is my script for /Pipe Init/BGloop/etc In C#

using UnityEngine;
using System.Collections;

public class BGLooper : MonoBehaviour {

int numBGPanels = 6;

float pipeMax = 11.53f;
float pipeMin = 14.2f;

void Start () {
	GameObject [] pipes = GameObject.FindGameObjectsWithTag("Pipe");

	foreach (GameObject pipe in pipes) {
		Vector3 pos = pipe.transform.position;
		pos.y = Random.Range (pipeMin, pipeMax);
		pipe.transform.position = pos;
	}
}

void OnTriggerEnter2D(Collider2D collider) {
	Debug.Log ("Triggered:" + collider.name);

	float widthofBGObject = ((BoxCollider2D)collider).size.x;
	Vector3 pos = collider.transform.position;

	pos.x += widthofBGObject * numBGPanels;

	if (collider.tag == "Pipe") {
		pos.y = Random.Range (pipeMin, pipeMax);
	}
	collider.transform.position = pos;

}

}

i just added a 2d boxcollider and made it some what bigger and then checked “Is Trigger” then it works