How do you catch the eye of the people in a city like Berlin, with hundreds of new posters every day on every wall, and where everyone is trying to sell it more or less the same way? Maybe hiding the info and making people research for themselves the information, joining like this the concept of the event?
This poster campaign can be explained as an experiment in phenomenology. The first aim of phenomenology is to reawake a sense of wonder about one's enviroment. People are not used to seeing advertisments for which the motive is not totally obvious.