Interesting conditioning experiment

I've been trying an experiment lately. It seems similar to what others have done in the past, but I've not seen anyone do this specifically.

When I'm going to sleep, I stare into the darkness you see when you close your eyes, and I try to get a "wall" to materialise. It's quite a passive action - I don't really try really hard to imagine it, but I try to let it happen. Sometimes it does (sort of) and sometimes it doesn't, but I don't force it. I don't try to dictate where the wall will appear - sometimes it seems like it's far away, sometimes it seems like it's a couple of inches from my eyes.

In dreams I'm often seeing surfaces that resemble the weird grey/black blobbiness. It's always been a surface so far. This may act as a dreamsign, or there may be some other way it can help to achieve lucidity. I will keep doing this exercise and see where it goes. So far I haven't used it with WBTB because I only do WBTB if I wake naturally and recently I've been sleeping right through.