In order to promote the tours it offers that take place at night, the Johannesburg Zoo created a series of shadow posters to make these alternative ways to experience the zoo known.
Creating the shadow posters involved cutting out a bunch of seemingly abstract shapes. Although looking at the posters in a well-lit room didn't reveal the animals hiding within, they could be drawn out by holding light from a mobile phone under them. Once this was done, the dynamic displays got kids and parents alike excited about the creatures that can't normally be seen during a day trip to the zoo.
Since viewing the shadow posters required people to have a phone in hand, this made it easy to prompt parents to go to the zoo's website and arrange a visit through a mobile device.