Indonesian hotels have these arrows on their ceilings which point in the direction of Mecca so that people will know which direction to face when they pray. Recently, however, there has been confusion in Indonesia as the highest Islamic authorities have stated that their previous calculation of the direction of Mecca was incorrect, and that it pointed to an area to the south, like perhaps Somalia. So I’m not sure where this arrow actually points, but I’ve read that it is ok to pray in the wrong direction as long as you do not intentionally do so. Still, I wonder what places like hotels are doing about this.