Sample trajectories for the secular evolution of the spin axis of the primary ŝ₁, plotted against the unit sphere for different values of κ = ν₂ /ν₁. The initial conditions are fixed, and shown for the primary as a dashed line from the origin to ŝ₁(0). The colours are interpolated between blue and red from initial time to respectively. The black axis represents the direction of ê_z. The behaviour for the secondary is analogous, up to a swap of initial conditions and κ → κ⁻¹ = ν₁ /ν₂.