Evolution of the Lyα line-to-continuum escape fractions ratio, f_esc(Lyα)/f_esc(UV), as a function of the dust optical depth in six different extremely clumpy shell geometries. The left panel illustrates the results of HO06 (Fig. 18 of their paper), whereas the right panel shows those of our own simulations. Note the different vertical scales. Each clumpy shell geometry is characterized by different values of N₀ and is built with a different set of parameters. Both structures showing N₀ = 1 (dotted lines) are built by adopting FF = 0.10, CF = 0.38, n_IC/n_C = 0, T = 10⁴ K, = 10²²/cm^-2, and v_exp = 50, 250 km s^-1. Both structures showing N₀ = 4 (dashed-dotted lines) are built adopting FF = 0.15, CF = 0.70, n_IC/n_C = 0, T = 10⁴ K, =10²² cm^-2, and v_exp = 50, 250 km s^-1. Finally, both geometries showing N₀ = 10 (solid lines) are built with FF = 0.13, CF = 0.90, n_IC/n_C = 0, T = 10⁴ K, =10²² cm^-2, and v_exp = 50, 250 km s^-1. In the left panel, each curve is obtained by assuming f_esc(UV) given by Eq. (17) and, respectively, f_esc(Lyα) = (0.94; 0.68; 0.38) for 50 km s^-1 and (0.81; 0.43; 0.18) for 250 km s^-1 in all clumpy media (N₀ = 1;4;10). Conversely, all curves shown in the right panel are derived from full Monte Carlo simulations. As in HO06, the Lyα escape fraction is derived in our simulations at the line centre (i.e. the intrinsic Lyα line is described as a delta function in all simulations).