I thought that the design of this ad campaign was so ingenious! The ANAR Foundation, a Spanish organization which helps kids in risk faced a problem in their most recent ad campaign. They wanted to make their their organization known, however, they did not want potential aggressors to see that a kid was even looking at the ad. The solution: using Lenticular printing on the street signs.
Lenticular prints are unique in the way that they display different images to viewers at different angles. ANAR created a poster that conveys a secret message to people at lower heights, even if accompanied by a potential aggressor. They calculated the average height of a 10 years old kid and planted a message only seen when looking at the poster from that height. Adults see an innocent poster of a normal kid, yet children would see a bruised kid and a phone number for the hotline. I think this is just brilliant.