[FakeComments]

I think co-calzone is probably most sensible.

Though the whole topic is a mess: an open-faced sandwich suddenly is a self-dual food.

[AaronFriel]

Self duals are entirely reasonable! A unified theory of food would be incomplete if we excluded such beautiful symmetries.

[andybak]

So where are we heading?

It seems we might slip from group theory to category theory. At which point we are surely describing the structure of meta-sandwiches (in that they sandwich various definitions of sandwichness between each other)

[AaronFriel]

I think you're onto something, after all burritos are just endofunctors in the category of monoids.

[wtfrmyinitials]

So called "open-faced sandwiches" are not sandwiches.

[DrScump]

Projected into two dimensions, they are.