But a small startup is ready to sell its foldable phone for real. The device is called the Royole FlexPai, and it started shipping in December.
The phone features a bendable 7.8-inch AMOLED screen that's made out of flexible plastic and has a 1,440-pixel resolution.
Running along the back of the FlexPai is a hinge, so you can bend the device in half as if you're closing a book.
The FlexPai has a fingerprint scanner and dual-SIM capabilities. It charges via a USB Type-C port and does not have a headphone jack.
When it's closed, it functions as any standard phone would, and depending on what side of the screen you hold it by, you can navigate on a screen with either a 16:8 or 16:9 aspect ratio.
Other specs include a 2.8GHz octa-core Snapdragon chipset, expandable memory and a 3,800mAh battery that can charge rapidly using Royole's proprietary charging technology, Ro Charge.
Below the display are the phone's two cameras: a 16-megapixel wide-angle camera and a 20-megapixel telephoto lens. The cameras act as both the rear and front-facing shooters when you fold the screen together.
You can leave it bent and propped up, or close it altogether, wherein it'll snap together with embedded magnets.
The FlexPai runs an OS called Water that's layered on top of Google Android 9.0. Whichever way you choose to hold or bend the device, the screen adjusts to the many different orientations and viewing options.
Royole's background in flexible displays uniquely positions it to create a viable flexible device, and the company has been working on the FlexPai for six years. It's also pouring $30 million into developer support.