Distances, , of the BS, AP, and the MD in its most distended (max) and compressed (min) positions along the central axis of the 2D models (Table 3) against the respective TS distance, r_TS, making use of both logarithmic (left ordinate axis, filled symbols) and linear (right ordinate axis, empty symbols) scaling; the abscissa has been scaled linearly. The AP has been plotted on both scales. Colours as in Fig. 2 with the exception of the linearly scaled AP (purple dotted line).