private function getPositiveOrientedAngle(refCell:Point, cellA:Point, cellB:Point) : Number
      {
         switch(this.compareAngles(refCell,cellA,cellB))
         {
            case SAME:
               return 0;
            case OPPOSITE:
               return Math.PI;
            case TRIGONOMETRIC:
               return this.getAngle(refCell,cellA,cellB);
            case COUNTER_TRIGONOMETRIC:
               return 2 * Math.PI - this.getAngle(refCell,cellA,cellB);
            default:
               return 0;
         }
      }

      private function compareAngles(ref:Point, start:Point, end:Point) : int
      {
         var aVec:Point = this.vector(ref,start);
         var bVec:Point = this.vector(ref,end);
         var det:int = this.getDeterminant(aVec,bVec);
         if(det != 0)
         {
            return det > 0?int(TRIGONOMETRIC):int(COUNTER_TRIGONOMETRIC);
         }
         return aVec.x >= 0 == bVec.x >= 0 && aVec.y >= 0 == bVec.y >= 0?int(SAME):int(OPPOSITE);
      }

      private function getAngle(coordRef:Point, coordA:Point, coordB:Point) : Number
      {
         var a:Number = this.getComplexDistance(coordA,coordB);
         var b:Number = this.getComplexDistance(coordRef,coordA);
         var c:Number = this.getComplexDistance(coordRef,coordB);
         return Math.acos((b * b + c * c - a * a) / (2 * b * c));
      }

      private function getComplexDistance(ref_start:Point, ref_end:Point) : Number
      {
         return Math.sqrt(Math.pow(ref_start.x - ref_end.x,2) + Math.pow(ref_start.y - ref_end.y,2));
      }

      private function getDeterminant(aVec:Point, bVec:Point) : int
      {
         return aVec.x * bVec.y - aVec.y * bVec.x;
      }

      private function vector(start:Point, end:Point) : Point
      {
         return new Point(end.x - start.x,end.y - start.y);
      }