What do we call this?
Hand signs on the wall? Hand gestures?
Shadow play, hand shadows, or shadow puppets will all probably be understood, although when I hear "shadow puppets" I usually think of things like this:
An older name for shadows thrown by hand is simply hand shadows. I've got this book, originally published in 1859, facing me on my bookshelf right now:
It can be called hand(s) shadow puppet.
- A play presented by casting shadows of puppets or actors on a screen. Also called shadowgraph, shadow show.
Its just called
hand shadows. If a story is told using that then its called
shadow play with hands. A shadow play may consist of
hand shadows and
shadow puppets(shadow puppets are usually cut-out shapes of puppets).