Numerical simulation of the intervelocity deprojection of a sample of 1200 pairs (left figure) and 13 000 pairs (right figure). The original 3D velocities have a Gaussian distribution of standard deviation σ_v = 90 km s⁻¹ and peak velocity 190 km s⁻¹ (cutoff on V = 0) [red curve]. We randomly project a random realization of this Gaussian distribution, then deproject it using the constant bin method with a bin of width 30 km s⁻¹ (left figure) and 20 km s⁻¹ (right figure, see text). The blue histogram is the mean result of 100 realizations of such a projection/deprojection and the black lines are the ± 1σ lines.