(Top panel) Profiles of an emission line from an optically thin pressure supported structured accretion torus viewed at different inclinations i. The dynamical parameters of the torus are n = 0.21 and r_k = 12 r_g. The black-hole spin parameter a = 0.998. The ratio of the gas thermal pressure to the total pressure β = 1.235 × 10^-5. The radius of the inner boundary r_in = 8.528 r_g and the radius of the outer boundary r_out = 20.246 r_g. The line emissivity is proportional to the density ρ. These line profiles are normalised such that the line flux F(E₀) = 1 when the torus is viewed at i = 60°. (Bottom panel) Profiles of composite profiles from two emission lines. The torus and black hole parameters are the same as those for the lines in the top panel. The line energies are such that one line has an energy 10% higher than the other line and the emissivity of the line with the higher line centre energy is 14% of that of the line with the lower line centre energy (cf. analogous to the relative properties of the Fe Kα and Kβ lines, Hölzer et al. 1997).