Percolation functions of model and observational samples: left panels: lengths of largest clusters and voids, ℒ(D_t) = L_max/L₀; centre panels: filling factors of largest clusters and voids, ℱ (D_t) = V_max/V₀; right panels: numbers of clusters and voids, N(D_t), as functions of the threshold density, D_t. Lengths and filling factors are expressed in units of the total lengths and volumes of samples. Top panels represent the DM model L512; bottom panels represent the SDSS samples. Percolation functions are found using smoothing kernels of radii 1, 2, 4, and 8 h⁻¹ Mpc. Solid lines show data on clusters, and dashed lines on voids. Indices show the smoothing kernel length in h⁻¹ Mpc. Number functions N(D_t) of DM models in this figure correspond to small system excursion limit N_lim = 50 cells.