Invisible/Hidden Window for WW Animations

[Neodarkside]

So based on my topic here, I had an idea that I'm curious if anyone has already or can make easily? I'm sad barely anyone uses the Invisible Wall Sex Marker from WW, however many of the Window animations are very much what I am interested in, sex against a wall. So I'd like to figure out how to make a Window but have it entirely invisible. I don't want the wall to be invisible, just the window as I am probably going to put it on the inside of a room. A quick google search has invisible windows but it makes the wall disappear instead.