So what would a breaded thing count as? Like a chicken or fish stick? It wasn't "filled" in any direction. At the extreme you could have a breaded, fried donut hole - a sphere that had bread deposited onto it (i.e. the donut hole is the filling of the sandwich), no axis at any stage, and you eat it from all directions equally.
Every sandwich has an axis. The axis is through the filling. You can roughly divide all sandwiches based on whether you eat along the axis (what we called axially), or around it (what we called radially).
A burrito is consumed axially, while a crunchwrap supreme is consumed radially.
Hope this is interesting, we’ve found pretty much every sandwich can be classified as radial or axial, which seemed like an achievement.