What does this sign indicate?

• Only vehicles on the main road must stop.
• Only vehicles on the cross street must stop.
• All vehicles approaching the intersection must stop and yield to other vehicles that had arrived first.
  Explanation:

  "A four-way stop sign requires all vehicles approaching the intersection to come to a complete stop. The right-of-way is determined by the order of arrival: the first vehicle to stop is the first to go. If two or more vehicles arrive at the same time, the vehicle on the right has the right-of-way."
• Vehicles can proceed without stopping if there is no visible traffic.