There was a battle ship out in the waters, and the captain was out on the bridge and observed that he could see lights and there was another ship in the distance, so he said to the signalman “Please send the message that you need to change your course by 20 degrees.” And so they got a reply back immediately, “you change your course by 20 degrees”. So then the captain said to the signalman again, “You tell whoever that they are to move the course... It's a directive by 20 degrees.” And the message came back, “you move by 20 degrees.” Finally, the Captain said, “You tell them that we are a battleship and to move their course by 20 degrees.” And the message came back, “we are a Lighthouse.”
A lighthouse. Immovable. Unshakable.