The only thing I disagree with on what that woman said in the 2nd vid, I really doubt this is a one way visibility thing, unless they have some new technology that can direct light in just one direction (without a mirror on the other side). For example, if it's night and the light is on inside, I'd bet people outside can see what's on the display. Might be kinda cool to have an outside movie night thru the windows tho.
Very basic physics lesson coming up.
Interesting fact: liquid crystal doesn't block light, they polarize it (force it to "rotate" in a specific direction) as it passes through them. The darker the colour, the more polarized (rotated) it becomes. In order to actually see the light, vs other non-polarized light, a second layer is required in front of the crystal. So an LCD monitor consists of backlight->liquid crystal->polarization mask, with the polarization mask only letting through light that has been rotated, and the more rotated the light is the darker that colour of that light: white is rotated to 90 degrees, black is rotated to 0 degrees (or the other way around, I forget) with shades of grey in between. This leads to an interesting trick you can do: if you open up an LCD monitor and peel off the mask in the front, all you (or anyone else) will see is a blank white screen. If you then cut glasses-shaped lenses out of that polarization layer and stick them in some frames, you can make a screen that can only be seen while wearing them.
Be sure that you mount the lenses correctly. Rotating the mask 90 degrees results in the opposite polarization: white becomes black, green becomes purple, red becomes... whatever blue and green make... yellow I think? And all vice versa
You can see this if you own some of the more expensive polarized sun glasses. Look at the screen and you'll notice some of the colours go weird, especially if you start tilting your head to the side.
This has the convenient effect of working the other way as well: unless someone puts a polarization mask against the outside of the window or are wearing special glasses like I'm sure you're all going to build now, no one will see what you're looking at; it's all just a mash of white light, some of which is rotated to 0, some rotated to 90, most in between, but except for a very few people, our eyes can't see polarization, all they'll see is white. It's only with the addition of the mask that the 0 degree light is blocked and the image becomes clear.
edit: clarified LCD vs the liquid crystal inside it.
