EDIT: i have no clue how to delete a post, i'm stupid.

With the new AR, it's really cool to be able to look and walk around with a phone! How about using our head, too?

Here's the idea: While using the front-facing AR camera, the other camera is pointing towards the face, assumedly. This could then be used for small head movements (shaking your head yes or no, etc.), or even things like blinking or accurate mouth movements. The possibilities are endless! :)