Angular characteristics of selected scattering phase matrix element ratios for the sample materials: the minimum versus maximum values of a_2r (top left), a_3r in the backward-scattering direction versus the same element ratio in the forward-scattering direction (top right), the minimum value of a_4r versus the same ratio in the forward-scattering direction (bottom left), and the extreme value b_2r↕ in the absolute sense versus the corresponding scattering angle, θ_34↕ (bottom right).