The idea is to use existing technology to create a system that would turn any wall into a "transparent" one.
On one side, a huge LCD panel would cover the wall, and on the other side, a small set of cameras would record the surroundings. The panel would project a live video and sound of the outer space. The user would be able to turn off the sound (mute) and/or the video, change it to play anything else via the Chromecast-like device, or mimic the wall.
The concept of transparent walls is usually achieved with glass. On the one hand, glass looks very elegant, but needs to be cleaned and is very fragile, since it cannot carry the heavy load or withstand bigger forces. The see-through walls are the concept that could be installed on older buildings, on any wall, doesn't need to be cleaned and can be turned into a regular wall anytime.
people could use this system to create sort of a customizable open space in their apartments
small offices could use this to create huge "windows" on hard concrete walls
doctors could see the number of people in front of their office with a click of the button
Stream other content than just a camera live video from the other side of the wall:
business meetings and conferences could be held via video meetings with all the people seeing the speaker on a display
teams that work in a dispersed offices could become "neighbours"