The Rollercoaster Principle

I was asked recently to clarify a point on open faced sandwiches. Here is Patricia's question:

"After our discussion concerning Danish open faced sandwiches, I have a question for you: As you know this type of sandwich is correctly eaten with a knife and fork... my question to you is: what if the sandwich is flipped and the filling is on the bottom and the bread on top? It MUST now be eaten with a knife and fork but is it still a sandwich? Just some food for thought!"

Here is my response:

If an open-faced concoction is deemed to be a sandwich, then flipping it over will not change its classification.

Here's why: If it's determined to be a sandwich in its upright form, this indicates that the item is not excessively messy (for more, see the Complete, Unambiguous Sandwich Definition). We're talking no gravy, no major sauce coverage. So, if flipped over, I'm assuming that there is a way to hold the thing
without getting too much of the contents/condiments on you. Ergo, it is still a sandwich. I.e., you could hold the meat with your thumbs, and tuck any pickles between the meat and the frame. If it's a loose meat sandwich, then we are in some trouble. At this point, if you insist on eating it flipped over, I suggest you eat over the sink.

The greater principle here is that a sandwich's classification cannot be affected by its angle of rotation. I will heretofore call this the Rollercoaster Principle: If it's a sandwich at the bottom of a rollercoaster's arc, then it's a sandwich at the top, when the passengers and their sandwiches are upside down.