Click on the image for a larger view. 1992 Nature 355, 524. The movies listed below were obtained by running my hydrodynamic code at lower resolution. Parcels of gas are exchanged between the cells, thereby approximating the flow in real space which is, of course, continuous and not cellular. The number of cells in a given space direction indicates the resolution, or precision, of the simulation.
Computation time increases very quickly when the resolution increases.
Even such computations can take quite a long time. Black indicates high values, white is low. You may see clearly that the nebula is cylindrically symmetric. Notice also the parabolic caps sticking out at the ends, and the rings around the waistline and around the main bubbles. These are due to turbulent ripples propagating up into the cavities blown by the wind from the central star.