Evolution of the inclination and line-of-sight velocity for the best-fitting simulated cloud during the period of the observations. Left panel: sky projection of the simulated cloud at t = 2003, 2008, 2012, 2016, and 2021 yr. The particles are colored from tip to tail from black to yellow. The gray shaded lines show the observed slope of the ridge of X7 at the same epochs (length not to scale). Right panel: line-of-sight velocity of the particles as a function of time. The colors represent the corresponding particles shown in the left panel. This figure is analogous to Fig. 10 of Ciurlo et al. (2023).