iOS 8 is likely to be previewed in a few days. One of the potential iPad features that’s been talked about is split screen apps.

I don’t know if or how this feature will exist in iOS 8, but I do know exactly one way that it won’t, and that’s Microsoft’s implementation of this feature.

Insert story about cutting babies in half.

Or the adage about “Something must be done. This is something. Therefore this must be done.”

Yes, you can run two apps at once. Is it any good? Surface sales numbers.

So why doesn't it work all that well?

• Invoking it is weird.
• Both apps have to be able to display well in their awkwardly small viewports.
• Existing multitasking metaphors can now feel weird. i.e. “if I switch to a third app, does it replace App #1, App #2, or both?

So how might iOS introduce multitasking? I have no idea. But one idea would meet the basic criteria of “not batshit awful” might be:

• Swipe (2 finger, 1 finger, ?) from the right (both the direction of your recent apps, and an available system-wide gesture) to access a mini version of the app (if that app supports some new API)
• If app #2 doesn't support the new fancy mini-mode, it just does regular app switching
• When open, you can do some gesture from App #2 to swap the apps. maybe 1 finger in each app and twist?
• Swipe right on App #2 to close it.
• Some other gesture (doubletap? pinch-zoom?) expands App #2 to take the full screen.

So does it make more sense?

• Invoking it is probably still a little weird , but Apple is better at teaching people new habits and it would probably be the only big thing they had to learn that year. ( The Milo Criterion: products must mature no faster than the rate at which users can adapt )
• App #1's visual appearance doesn't change at all during use of App #2. This creates a consistency for the user. It also means it’s no developer work for App #1 to work in this arrangement.
• App #2 does require developer work, but in building a UI (that potentially targets a new, and maybe even relatively restricted API) for this special mini mode, it should hopefully work well with whatever system wide gestures and conventions are needed to make the whole idea work reliably.

Some other thoughts:

1. App #2 is undeniably “on top of” App #1, but a little skeumorphic depth between friends isn't so bad, especially if you recently flattened the bejesus out of your entire OS.
2. iOS is getting pretty decent at dealing with swipes from off-screen. Notification center and control center both have that little nubbin for if it’s not sure you want it or not.
3. How do you select which app shows up as the 2nd app? only the last one seems limiting, but getting a list seems crude, maybe a gesture cycles App #2 through the recent app stack while keeping App #1 stationary. I’m sure they’ll think of something.
4. If Messages and Mail ship with this ability (i.e. no public API at all) I think plenty of users would be ecstatic right there.
5. Facebook messenger could ship with this and only this mode and I’d be happy with it.
6. Previous point generalized, what would it feel like to have a tapping a notification launch into this view in lieu of launching the full app? Would the notification need to surface that fact, or would it just feel fine?
7. Clipping apps (Evernote, Vesper)
8. Where does a better share-sheet end and a decent way to invoke this for any app begin?
9. Are there any two-app tasks that would be empirically better in a side-by-side split-screen configuration instead of an overlay configuration? movie + imdb? browser + spreadsheet? photo app + snapchat?