The photographs indicate the way in which a cook marks his orders. These secret plate markers allow a Waffle House cook to simultaneously prepare multiple customer orders at once.
Let me give you an example. If I were to order three scrambled eggs, dry wheat toast, and hash browns, the waitress would face the grill and yell out loud – "Mark: Triple scrambled dry wheat plate."
The cook would then quickly take a large dinner plate, turn it sideways, and place a tub of jelly upside down at the six o’clock position.
The six o’clock position indicates scrambled eggs, and the jelly upside down means wheat toast. I am not sure how to mark "dry" for the toast, or how to indicate hash browns versus grits.
This chart explains why I often get a packet of mayonnaise with my grilled chicken plate.
via Flickr http://flic.kr/p/zsUEZ