I’ve decided my solution is a bit complicated for Loop String 3, so I decided to post parts of the puzzle to help. These are not solutions, but simple starting points, all you need to do is lower the energy of the stacks.
Here is the top
thanks brourd - that’s about where I got to - before I needed to go do other things, - didnt realise that tweaking the stack energy might make a difference to whether all the loops might close or not I’ll go look at that again when I get a moment.
Oh, I forgot to mention, the amount of energy raised will be minimal, that is what constitutes the trick