Test-particle streams in the true λ - φ frequency (top) and angle (bottom) spaces after 10 Gyr of evolution in the Kuzmin-Kutuzov potential. The colours represent the energy gradient with the most bound particles in yellow and those least bound in blue. The panels have been centred on the current position of the centre of mass of the progenitor system. The insets give the best-fitting slopes to the distributions as well as the angle-frequency misalignment ΔS.