Two plagues, and between them a purpose that has nothing to do with Pharaoh: the signs are happening so that a grandchild can be told about them. The locusts arrive on an east wind and leave on a westerly, which is how swarms actually move, and are blown into a sea the Hebrew calls yam suph — the first time that name appears in the Bible. Then a darkness that can be felt. The negotiation collapses over one question: who is allowed to go.