var originalObject : Transform;
var reflectedObject : Transform;

function Update () {
    // Makes the reflected object appear opposite of the original object,
    // mirrored along the z-axis of the world
    reflectedObject.position = Vector3.Reflect (originalObject.position, Vector3.right);
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public Transform originalObject;
    public Transform reflectedObject;
    void Update() {
        reflectedObject.position = Vector3.Reflect(originalObject.position, Vector3.right);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public originalObject as Transform

    public reflectedObject as Transform

    def Update():
        reflectedObject.position = Vector3.Reflect(originalObject.position, Vector3.right)