Here is what happens:
– you remove a billet from a stack, hand it to a person and ask them to draw a simple drawing (you can ask them to write/draw anything)
– the billet is placed face-down into the stack
– you place the stack on the table/in your pocket/in their hands if you’re ballsy
– you got a full peek

This is a DIY project, and you already have all the materials.

It’s extremely easy to use, easy to build, and it is just-about angle-proof.