Gene, I've never popped the cover off one of those things since it was never my place to do so. I've only seen them in passing (hallways, etc.) in other people's properties. Don't want to go poking around in what's not mine, you know. [Linked Image]

I understand what you mean about the concrete wall. What I've found amusing is sometimes how a poured concrete wall retains the ridges and graining of the plywood molds after the wood panels are taken off and the wall is painted. You look at it and you think someone painted over the wood instead of concrete.