plait fog

verb2

1. •
   (UK) Used as a metaphor for accomplishing an impossible task.

   • Just as you can't plait fog, you can hardly have an informed debate about something that means quite different things to different people. — 2010
2. •
   (UK, figurative) To perform an action in which the result falls apart immediately or to work on organizing something that cannot be organized.

   • He believed that the project was largely "plaiting fog” and making too much of what it had achieved. — 2003