Align Nipple

This design concept is a gizmo which you'd have in a first aid kit to help you if someone collapses and needs CPR. You'd whack it on the chest of the ill person, line it up and follow its instructions. It flashes to give you proper timing, and clicks to let you know you're using the right chest-compression pressure (it's harder than you think). It looks pretty simple, and is exactly the sort of thing that might help save a few lives in an emergency...if they ever manufacture it.