a wonderful use of technology

[miriam_e]

http://www.upworthy.com/watch-an-abused-child-get-a-secret-help-message-in-broad-daylight-that-his-abuser-cant-see

Lenticular optical systems have been around for a long time, usually for animated images or stereo, but I've never seen them used for such a cool social purpose. I hope this spreads around the world.