In recent years, the LG V10 and V20 touted a second screen as a signature feature (though the new V30 put an end to that). The Meizu Pro 7 switched it up a bit with a second AMOLED screen on its back, but we've covered second screens before. But a modern smartphone doubles up on more than just the screen. Two cameras are a staple of new flagships, for example. That was a thing way back in 2011 with the HTC EVO 3D and the LG Optimus 3D. The two cams were used for stereoscopic photos and videos back then. Today the second cam has either a wide or a tele lens, perhaps the sensor it uses skips...
Source: https://www.gsmarena.com/counterclockwise_two_is_better_than_one-news-27592.php
