Just for the record. This is what happens when you try to fit text in three different displays: the first one, a square display; the second one, a rounded display of the same size (let's say both are 2" displays); and the third one a smaller, rectangular display (let's say 1,5").
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The rounded display is the worst. So let's try with buttons, another extremely common UI object.
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Doesn't get any better. You can only fit three buttons (instead of four) and you have to make them shorter than in both the square display of the same size and the rectangular (smaller display). Of course, you can make the button in the middle longer, but why would you want one of the buttons to be bigger than the others?
Let's try with a list. You'll need a list at some point right? IE, when you need to select a song from an album you want to listen.
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Ew. Doesn't look good at all.
Yes, you can design new interfaces, but I doubt you can make one without buttons, text or lists usable. You'll need to display text. One of the main features is that it displays a notification (with text) when you get it on your iPhone. So why would them choose the option that displays LESS text from all the options available?
If you think it's possible to solve this problems, please explain me how.