Someone has to be in the other one. It works like this:
Lightning A - Pushes
Lightning B - Stays still
Lightning B appears to move on Lightning A's screen, but it doesn't. If lightning A pushes B for a bit, and stops, Lightning A will slide back into position. If Lighting B is pushed far enough, lightning A will be thrown, sometimes VERY far. Today, a lightning got thrown HALFWAY ACROSS THE SANC!
Used to be one where you could launch vehicles with a capitol shield.
Was fucking great. Park prowler on the shield. Get out. Watch it fly over the treeline.