code: function(x, y, k, shift) {
  
        var s = this['SCALE'];
  
        if (k === undefined)
          k = 4; // How many regions? 4 = quadrant, 8 = octant, ...
  
        if (shift === undefined)
          shift = 0; // Rotate the coordinate system by shift° (positiv = counter-clockwise)
  
        /* shift = PI / k, k = 4:
         *   I) 45-135
         *  II) 135-225
         * III) 225-315
         *  IV) 315-360
         */
  
        /* shift = 0, k = 4:
         *   I) 0-90
         *  II) 90-180
         * III) 180-270
         *  IV) 270-360
         */
  
        var phi = (Math.atan2(y, x) + TAU) / TAU;
  
        if (Math.abs(phi * s % (s / k)) < EPS) {
          return 0;
        }
  
        return 1 + mod(Math.floor(k * shift / s + k * phi), k);
      }
docs: Returns the quadrant
  
  @param {number} x The point x-coordinate
  @param {number} y The point y-coordinate
  @param {number=} k The optional number of regions in the coordinate-system
  @param {number=} shift An optional angle to rotate the coordinate system
  @returns {number}