Fig. 7
From: Observation of nonlinear fractal higher order topological insulator
Schematic illustration of third generation G3 of the Sierpiński gasket. The intra-cell couplings between sites (gray circles) are indicated in this plot with thin red lines, while inter-cell couplings are indicated with thick blue lines. The intra-cell and inter-cell coupling strengths are given by t1 and t2, respectively
