In Super Mario World (and many other Mario-related Nintendo titles), there are different power-ups that give Mario different abilities. For example, the regular mushroom makes Mario bigger (from mini-Mario), the feather give Mario a cape and helps him glide, the Fire Flower allows Mario to shoot fireballs, etc.
However, the 'backup power-up,' or the power-up you will receive when you are damaged and lose your current power-up (which is held in the blue box in the middle of the top of the screen) changes on what power-up you have when you get a new power-up. For example, if you are larger Mario and you get another regular mushroom, your 'backup power-up' will be a regular mushroom, since you're not mini-Mario.
What is the order/pattern of these power-ups. If you have a fire flower and you get the feather, what will be your backup powerup? Is there a flowchart for how power-ups and backup powerups are handled?