Polar area diagrams showing flows in four quadrants in the three subfields. The percentage of BPs in a quadrant that move towards (blue) and away from (red) the reference point are represented alongside those BPs that experience no change throughout their lifetime (green). The percentage for each flow direction in each individual quadrant is stacked as concentric arcs to aid the visualisation of flow directions within a quadrant. a), b), and c) show the flows with reference to the centre of the subfield in region 1, 2, and 3, respectively. d) shows the flows with respect to the neutral line found in region 3 with HMI LOS magnetograms.