All hail the original Android rollerball
Android started its journey into weird and wacky add-ons with the rollerball on the first ever Nexus One. Back then, you could navigate through Android home screens using the touch-swipe mechanism or by rolling left and right on the rollerball, placed in the same area as the former Home button on the iPhone. Other Android phones adopted this feature, including my first ever Android phone, the HTC Incredible. But it was eventually phased out to make more room for the screen.
