iRiS - http://project-iris.org/

By combining a recently developed mobile software application with the multimedia facade of the ARS Electronica building we intend to lower participation barriers for end users when interacting with such facades.
We developed two prototypes: in the first application, users can paint interactively on the building using touch input on the mobile device. In a second application, users are able to solve a jigsaw puzzle displayed on the facade.
iRiS (Immediate Remote Interaction System) is a joint research project from the University of Saarbrücken, Germany and University of Munich, Germany.