There is an exhibit currently on at the Tate Britain art gallery. It is out in the street out front of the gallery and from the outside it looks like a box with mirrors making up all four walls plus the roof.

Inside there is a fully plumbed in toilet. However, the mirrors are one-way glass so from inside you can see out, but from the outside you can't see in.

Apparently it's quite liberating, if not a little unnerving to sit there and evacuate while being able to see the whole world go by.

I would be pretty scared of using that - I would worry that it's some kind of hidden camera gag where as soon as you sit down and start doing your thing, somebody presses a button and it turns to clear glass like the LCD panels you mention.

When I was young we used to go to agricultural shows and the toilets there were pretty basic - pretty much a large pit and a plank of wood with a hole and plywood walls. Then again, that was probably luxury to most of the visitors.

Gareth