code: function DunFile(startCoord, rawPillarData, dunName) {
      this.startCol = startCoord[0];
      this.startRow = startCoord[1];
      this.fileName = dunName;
  
      this.rawPillarData = rawPillarData;
      this.rawColCount = this.rawPillarData.length;
      this.rawRowCount = (this.rawColCount > 0) ? this.rawPillarData[0].length : 0;
  
      this.pillarData = null;     // Initialized during unpack operation.
      this.colCount = this.rawColCount * 2;
      this.rowCount = this.rawRowCount * 2;
  }
docs: DUN files contain information for arranging the squares of a TIL file.
  Multiple DUN files can be pieced together to form entire levels.
  For example, the 'town' level is a combination of 4 DUN files.
  
  In addition, DUN files also provide information regarding dungeon
  monsters and object ids.