Fig. 1. Schematic view of the logical structure of the fractal model. Black boxes contain the causal core of the model, namely its three premises (i-iii), mass conservation (C.a) and scaling (C.b). The three primary independent consequences (PIC) WBE obtain by combining elements from the causal core are shown in red, green and blue boxes. Arrows `SIC 1' to `SIC 4' indicate the secondary independent consequences WBE need to prove from the core. Then, another step of combining boxes is done by WBE to obtain a simplified equation of the circulating fluid from WBEeq. 4. A final round of merging PICs and SICs boxes is needed to obtain the putative scaling exponent a, in WBEeq. 5. Notice, also, that PIC 3 `re-enters' the causal core in the energy minimization proposed by WBE, by means of a `volume restriction' term. This is discussed in section 2.