3D snapshots of the z-component of the vorticity ω = ∇ × u for the nonrotating case (panel (a)) and rotating case (panel (b)), both cooling with a decreasing flux from the top boundary. For both cases, the snapshots are shown at the same time, when the heat flux that drives convection has decreased to 10% of its initial value. The Rossby number of the convective flow in the rotating case is Ro ≈ 0.01, computed using the averaged flow velocity in the convection zone and the thickness of the convection zone. At t = 8 × 10⁻², the convection zone depth in units of the box size H is h = 0.37 for the rotating case and h = 0.56 in the nonrotating case.