Triangle is "back", actually; the circle is "home". And the square thing is the app switcher history thingie. More evidence, I suppose, that the new icons are

Triangle is "back", actually; the circle is "home". And the square thing is the app switcher history thingie. More evidence, I suppose, that the new icons aren't very intuitive. On the other hand, floppy disks haven't been used for anything for a couple of decades now but they're pretty universally understandable as save icons. Most of our icon vocabulary has meanings that we learn by rote memorization more than inferrence from their pictographic representations. I'm not sure that the difference between a "good" and a "bad" icon (as long as they're used consistently) really matters that much beyond first-use experience.