Sampling of the Babcock-Leighton nonlinearity f(B) for the two time-latitude diagrams of Figures 6A and 6B, along temporal cuts at latitudes 25° and 45°, respectively. The histograms display the sampling of toroidal field values along the cuts, and the color shading indicates the fraction of time spent at a given point along the non-linearity curve (dotted line). Note the marked magnetic polarity asymmetry in panel B.