While messing around screwing with things being a idiot as usual I found that you can make elytra invisible (Sort of anyways). So I played around with it and found that in f5 it ignores water and glass. After awhile I came up with this.....
-All entities are invisible when you are looking through elytra
Including Signs and chests
-It doesn't work with Lava
-you have to have 2 layers or more
-to see all of whats behind it you are limited to how much you can see in f5
So KooladeisBAE, why tell us this... i'm sure you already have many ideas in your head already but if you dont here is one.... you can hide a secret pattern behind the wall and that secret pattern can be the puzzle to the next room, kinda blunt but it is hard to figure it out.
Also to get invisible (sort of) elytra wings, all you have to do is put on frost walker 1 boots and not hold anything in your hand with elytra is on.