Snapshots of the ¹H (upper panels) and ¹²C (middle panels) mass fractions at t ~ 395 s (model A; left panels), and 688 s (model I; right panels). Lower panels: the number of blocks administered, at this stage, is 3184 for model A, and 43 800 for model I. In both simulations, FLASH divides each block in 8 cells. Structures such as vortexs are better resolved in the finer resolution model I.