anchor.diff:                    TwoSided = false }
   
               // fin
  -            (descriptor, size, vertexMap)
  +            (descriptor, vertexMap)
   
           // did not find albedo tile set
           | None -> failwith "Unable to find custom TmxLayer Image property; cannot create tactical map."
  
positive.code: 
  type Character = Character.Character
  
  type Occupant =
      | Character of Character
      | Chest of unit
  
  
negative.code:         | Some vertices -> vertices
          | None -> failwith ("Field vertex index '" + scstring index + "' out of range.")
  
      let tryGetFieldTileDataAtMouse field world =
          let mouseRay = World.getMouseRay3dWorld false world
          let fieldData = getFieldData field world
          let indices = [|0; 1; 2; 0; 2; 3|]
          let intersectionMap =
              Map.map (fun _ vertices ->
  