Very tricky--lenticular printing

Remember those Cracker Jack toys--a little picture that "moved" and changed back and forth if you tilted it this way and that?

OK, you don't even know what Cracker Jack is. Never mind.

Anyway, printing that can only be seen from one angle is being used in a clever poster by Mexico's ANAR Foundation--on the subject of child abuse.

It's a large poster of a boy's face--from the height and viewpoint of an adult, it's just a kid. But if a child is standing there, from a lower angle, the lenticular process shows the kid's face bruised and abused. There is also printing only the child can see that tells the tot where to go for help.

The printing is done on ridged material--when the ridges face down, the message only shows from below.

Can you think of other uses?

Go to http://www.anar.org for more info.