If bezel-less phones are the trend today, foldable could very well be the next. Smartphone makers, including Samsung, Oppo, and Huawei, have all been reported to be working on radical book devices, and just this week, a new hint surfaced suggesting Apple may jump on the bandwagon, too.

First spotted by Patently Apple, the United States Patent and Trademark Office (USPTO) published on Thursday an Apple patent application filed last year detailing an electronic device with a flexible display. The display could be bent toward or away from each other and used as a traditional iPhone when folded in half or a small iPad when opened flat.

The patent mentions an optically clear flexible adhesive and a shape memory alloy or amorphous metal as potential materials to allow the bending of the display. Apple may use liquid metal as well for the structure of the device and a micro-light-emitting diode (LED) display, which is more energy-efficient for the screen.

Apple's latest patent application comes on the heels of reports claiming that it is setting up an LG plant for production on foldable OLED panels. According to reports, the iPhone maker's rivalry with Samsung, which currently supplies the iPhone X displays, and concern over leaking are likely the deciding factors in changing suppliers.

Should the rumored radical iPhone comes to fruition, Apple will not be the first and the only one to re-introduce foldable smartphones in the market. Samsung is set to unveil a foldable device of its own dubbed the Galaxy X this year. Earlier this week, it accidentally published the handset's support page, suggesting its imminent release.

As for Apple's device, it is unclear when it will hit the shelves. Patent filings are no indication that a product will ever launch. The tech giant has submitted many patents throughout the years that never went into production, so the idea of a foldable iPhone is best to be taken with a grain of salt. Previous reports do predict, though, that it may come around 2021.