Synthetic CO J=2−1 channel maps, imaged at 40 m s⁻¹ spacing for each kind of model. The beam size is shown in the bottom left of the panels. The model type is indicated in the upper left: the top row shows the warped model, middle row shows the unperturbed disk with a radial flow, and the bottom panel shows a disk with a warp and a radial flow. We only show the channels close to the systemic velocity v_LSR = 0 k m s⁻¹.