"The size of a square should equal the size of the wall segments it is connected to. Think of a grid square as a cube with ground, four walls and a ceiling." So, I get that the movement needs to be along the grid and walls should match. However, the last time I made a first person maze in a game, I included walls that only existed between grid spaces. This wouldn't violate the rules as stated, but it also would mean having to have walls with thickness lying on the grid lines themselves to make them not look weird, which seems like a grey area. Also, the actual method I used was having a different internal representation of the grid in memory than shown on screen, with the internal version not having the same meaning for movement (non-existent grid spaces that would be skipped over).
Are either thin walls between grid spaces or the use of non-existent rows and columns in the internal representation of maps against the rules?