MIT student David Merrill has developed blocks, as big as a cookie, which respond to one another. For example, different videos in different blocks can react to one another, take over each other's colours, you can make a puzzle that needs to be solved in a specific time frame, play games like scrabble and make sums. Below a video.
Future Vision by Erwin Van Lun on this article
It looks like a game, and it is, but it also shows how all screens react to one another. Later, when we hold a mobile phone about a tv the video will slip straight into it. That’s how simple it’ll be. Piece of cake.