Lamp

using UnityEngine;
using System.Collections;

public class Lamp : MonoBehaviour
{
    public SpriteRenderer lampSpriteRenderer, skySpriteRenderer;
    public Sprite lampOn, lampOff;
    public Sprite skyOn, skyOff;

    void OnMouseDown()
    {
        if (lampSpriteRenderer.sprite == lampOn)
        {
            lampSpriteRenderer.sprite = lampOff;
            skySpriteRenderer.sprite = skyOff;
        }
        else
        {
            lampSpriteRenderer.sprite = lampOn;
            skySpriteRenderer.sprite = skyOn;
        }
    }
}