A library sight the other week:

Two very thin almost like fiberboard wall sidings, just laying on the floor on a side aisle.

I stopped and had to look close, to see if they were part of the tile, or were just laying on them, and when you walked on them like I did after I checked them out, you really didn't notice much of a difference in what you were walking on.

After I noticed them, too, I wondered how they got there.

I also thought that with that I was a lot like an Alzheimer's patient, since due to loss of thinking skills they often stop when tiles become carpet or a carpet becomes tile, since they see a difference between the materials but can't process exactly what's happening, a lot of times.