The design of the sandwich is a human invention that goes way back beyond recorded history. The basic grain-based food enveloping fats and protein with greens thrown in or not pretty much describes all of the best foods from 5000BC to now.
I personally am very fond of a good proper Ruben.
EDIT: I have to add....
My son recently discovered the joys of sandwiches. He is 5 years old. I now find myself making regular trips to the deli for good cold cuts of meats as a result of it. His favorite for the last week has been deli cut bologna with red and yellow dip and a slice of yellow cheese. That would be mustard, ketchup, and Colby cheese for the rest of us. lol At least he is off his hotdog kick.
I personally am very fond of a good proper Ruben.
EDIT: I have to add....
My son recently discovered the joys of sandwiches. He is 5 years old. I now find myself making regular trips to the deli for good cold cuts of meats as a result of it. His favorite for the last week has been deli cut bologna with red and yellow dip and a slice of yellow cheese. That would be mustard, ketchup, and Colby cheese for the rest of us. lol At least he is off his hotdog kick.