Comparison of the resulting ζ₂ maps (in units of 10⁻¹⁷ s⁻¹) on the two runs with distinct box sizes L but otherwise identical, using the BFL20 method. Panel a) shows the run with L = 0.3 pc (namely the reference run 2), and panel b) shows the results with L = 0.15 pc. The colorbar is kept fixed to ease the comparison. The histogram distributions are compared in panel c), labelled in the top-right corner. The median values (median uncertainties) are shown with the vertical dashed lines (shaded areas).