Trying to make a wall hanging able to be walked through

So I stumbled upon what I think is a glitch where I was able to have the "Tall Fluid Forms Lighted Wall" in front of a door arch and essentially made a hidden door. However, I can't replicate it. So I'm thinking there must be a way to make one of these that could do this intentionally. Either through tuning or some other method I don't know yet. I have a castle I'm working on for a trickster and honestly a room that looks solid with hidden doors is like the coolest thing I can think of. Any help will be appreciated so thanks!!