Re: Paper yes...
permanent markers on the whiteboards
I was in a meeting some years ago when someone was getting quite excited about the potential for the new product whose diagram was displayed on the wall. So excited, in fact, that he reached for a whiteboard marker to draw an explanatory line, only to look stunned by the yells of "No!!!, "Don't!!"
The diagram was being projected from someones laptop onto the projector screen that was pulled down in front of the whiteboard. Fortunately he did stop in time, although a little startled.