Since the 18th century the invention of the sandwich, named after English Aristocrat John Montauge the 4th Earl of Sandwich, humanity has made every type or variation of the sandwich.
As a child growing up in the US Midwest, where the phrase anything between two pieces of bread is considered a sandwich, and I mean anything.:-)
I remember days of eating mayonnaise, mustard, ketchup, jelly, peanut butter, and my favorite sliced banana sandwiches.
In my college days, I made sandwiches, separately with every type of lunch meat, pork, beef, chicken, and Cornish game hens.
In the military, I enjoyed pizza sandwiches, gator sandwiches, rattlesnake, lamb, and goat sandwiches. I had a friend place fired insects between two slices of bread and eat them. I passed on the bug sandwiches.
As an older, wiser, adult, I do not eat meat anymore, but, my desire to eat a sandwich has evolved to become my toasted morning breakfast sandwich.
I start with wheat bread filled with, spinach, arugula, tomatoes, red onions, black olive slices, sliced banana peppers, with a slice of Provolone cheese, balsamic vinegar, light olive oil, salt, and pepper.
My lunchtime sandwich has become a rye bread veggie sub filled with the earlier breakfast veggies, except I add sliced garlic & sliced jalapeno peppers. The spiciness is incredible.
My dinner salad sandwich is usually two slices of oat, bread, with spinach, cucumber, tomatoes, radishes, a splash of balsamic vinegar, a little light olive oil, salt, and pepper.
Grilled onions and garlic with sauteed, shrimp are the side dish, for my dinner sandwich.
There are many other vegetables I’m willing to try, so I foresee a future of ever evolving variations of my veggie sandwich, with fish and seafood.