Somehow related to this post on Pasta and Vinegar: Urinal innovation, I believe I have found something even more "disturbing"... a black sticker that unveils an image when piing. It turns back black when some fresh water comes down to clean the urinal :-)
I am not sure what the message was on the image but it might very well be an ad....

Needless to say it was quite tricky to shoot those pictures... and hopefully nobody came in :-)

Location: The Technopark in Zürich