Time evolution of stellar bar parameters for the three galaxy models. Top: evolution of the bar strength parameter (A₂/A₀) in the x/y-plane. Middle: evolution of the ratio of the Fourier m = 1 mode to the m = 0 mode (A_1z/A₀) in the x/z-plane. This quantity represents the growth in asymmetry normal to the midplane. Bottom: evolution of bar pattern speed (Ω_b). Models are shown as (blue) circles for the prograde model, (black) diamonds for the nonrotating model, and (red) stars for the retrograde model.