A recent update brought multitasking gestures to my original iPad. I hardly use them because swiping left never works and swiping right seems to launch random apps. What are the rules behind them?
Apps for the multitasking gestures are sorted by the time you last opened them, with some exceptions (see below).
For example, from your home screen open Mail, Safari, and Music, in that order. At this point, if you swipe from right to left, it will switch to Safari because that is the app you opened before Music. If you swipe from right to left again, you will go to Mail, because it was opened before Safari. Then swipe from left to right to go back to Safari, and repeat to go back to Music. Now, go to your home screen and open Safari. It has now been opened most recently, so swiping from left to right will give you the bounce effect. Swiping from right to left will open Music, and repeating will go to Mail.
An app is moved to the front of the swiping list when you open it from your home screen or from the multitasking bar. It will not change position in the list if you open it using multitasking gestures or notification center (unless it is a notification on the lock screen), unless it was not previously open.