optical

Looking down on an outside corner?

OR

Looking up at an inside corner?

I've been looking at these corners for 20+ years, and cannot quite decide which direction they project/recede. Once upon a time there was going to be a project to build a model corner and paint it with cast-off paint samples. That didn't happen, much as many photo projects don't. Which reminds me of one from this past March. Maybe we'll dive into that one next time?