Plastic Screen Media Decoder Answered
I've seen a print ad that had a plastic 'zigzaggy' decoder gizmo stuck to it, that I could peel off and use to 'decode' media as I slid the plastic over my screen, over a particular picture on their website. The refraction of the plastic would 'decode' the image.
What on earth would this kind of mechanism be called? I'm trying to Google 'something' of a how-to...
Not having found anything, I'm turning to the craftiest bunch I know ;)
Thanks for your help.