So we see that whenever a flip flop takes place, there is a certain amount of energy, a relatively large amount of energy that actually must be overcome. So there's a large energy barrier to this process. And that's because this process is energetically unfavorable. The interactions in this case aren't stabilizing like the interactions are in this particular case. So we conclude that these fossil lipids can move relatively quickly and easily along a leaflet in the lateral direction. But even though phospholipids can actually flip flop, they can move transversely.