Figure 3. Trajectories of coarse-grained primate cortices and other mammalian and human brains in ${\displaystyle K\times S}$ plane.

(A) Straight trajectories indicate self-similarity (described by a scaling law). In particular, the black line here indicates objects with ${\displaystyle A_e=A_t}$ for all scales, such as the box of finite thickness with a fractal dimension ${\displaystyle d_f=1}$ (grey data points). This line is reproduced in all subpanels for reference. (B) Morphological trajectories of multiple hypothetical fractal objects are shown which. A flat trajectory (constant ${\displaystyle K}$) corresponds to ${\displaystyle d_f=2.5}$ in this space. However, these objects are clearly different fractals with different values of ${\displaystyle K}$. (C) Hypothetical objects with overlapping straight morphological trajectories indicate multiple realisations of the same fractal object. Flat trajectories (constant ${\displaystyle K}$) correspond to ${\displaystyle d_f=2.5}$. The two hypothetical objects with a decreasing ${\displaystyle K(S)}$ correspond to ${\displaystyle 2<d_f<2.5}$ (D) Projecting our actual data into the normalised ${\displaystyle K\times S}$ plane showing the coarse-grained primate brains (same as in Figure 2) as data point connected with solid lines (colour-code same as Figure 2). Different mammalian brains are shown as grey scatter points, and adult human data points are blue.