Twist motion in the warped disk simulation. Top row: unit angular momentum vectors close to the inner (left panel) and outer (right panel) edge of the disk for the first t = 6000 yr. Similar to Fig. 17. Middle row: x-y components of the unit angular momentum vector at the same radii as in the top row, but only for the time period between 300 and 390 orbits at R₀, chosen to roughly show 1.5 precession periods. The direction of the precession is indicated by the arrows. x-markers show the beginning of the plotted time, squares the end. Diamonds indicate the middle of this time period (45 orbits after the x-markers). Bottom row: same as middle row, but for various radii, plotted with an offset of r/(60 au) in y-direction to disentangle the twist at different radii. The stars show the l_x−l_y components at a snapshot at t = 3696 yr (308 orbits at R₀), which shows a twisted state in the time evolution.