How would one do that? Visually, I mean. Even that would help.
Within your Game_Map class you'll find a @map object.
@map = load_data(sprintf("Data/Map%03d.rvdata2", @map_id))This object contains all table data for the map itself. Using this as a base you can mirror the x and z axis of the map fairly easily. This would allow you to visually mirror the map.
@map = load_data(sprintf("Data/Map%03d.rvdata2", @map_id)) p @map.data.methods for x in 0...@map.data.xsize for y in 0...@map.data.ysize for z in 0...@map.data.zsize p x.to_s + " " + y.to_s + " " + z.to_s p @map.data[x,y,z] end end endHowever, each tile is allocated a specific ID when you use the automapping features in the RPG Maker itself. Mirroring these tiles will cause many graphical errors, resulting in many tiles that do not fit in place. It would require additional algorithms to resolve the issues of automapping.
Vertical is another issue entirely, you'll run into far more errors attempting to mirror these. This, in my suggestion, should be avoided.
VISUALLY the tiles cannot be displayed in any other way than, left to right, top to bottom. The x, y, and z axis of the "graphical" viewport is hidden to the programmer.
If you were to actually mirror the tileset however, and use a mirrored form of a tileset for this exact procedure, theoretically you can do this.