Upper panels: P_ee(k, z) as fitted on spectra from the fourth simulation, as a function of scales (left panel) and of redshift (right panel). For reference, the fit is compared to data points for z = 7.8 (x_e = 0.26) and k = 0.14 Mpc⁻¹ respectively, with corresponding colour. The width of each line represents the contribution of the redshift (resp. scale) of the corresponding scale (resp. redshift) to the final patchy kSZ amplitude at ℓ = 3000. Lower panels: corresponding probability densities (dashed lines) and cumulative distributions (solid lines). Shaded areas correspond to the first 50% of the signal. The dotted vertical line on the lower right panel marks the midpoint of reionisation.