The first rank is for the direction 0, upwards. The other ranks are affected, clockwise, to an angle whose value is 360/number of ranks. So, with 4 ranks in the concerned dimension, the angle will move 90 clockwise for each direction change: second rank will be affected to 90 (rightwards), third rank to 180 (downwards) and fourth rank to 270 (-90) (leftwards).[2]