Comment Wall by Kinecity (Marek Walczak, Jakub Segen and Michael McAllister) is a wall where people can write their thoughts directly onto a wall using their fingers. The camera-recognition system remembers their text and displays it over time. The further away you stand from the wall; the most distant texts are displayed. As you come forward, more and more recent texts are uncovered until, when you are in front of the wall itself, a blank area is created for you to write your own.

from Tom Carden of Computing for Emergent Architecture