Huawei Mate XT Ultimate Design that was launched in select markets.
Samsung Patent Application Shows Device Could Feature Three Hinges 4r362v
A patent application on the WIPO website (via SamMobile) indicates that Samsung is working on a foldable device with four foldable s. These components are shown to be connected via three hinges. When unfolded, the smartphone appears to form a much larger display. The second and third are ed by a more complex hinge that allows the furthermost s to fold inward.

Samsung's foldable phone seen in folded and unfolded configurations (Tap to expand)
Photo Credit: WIPO/ Samsung
The document, which is titled 'Electronic device including bendable display', incudes drawings of the most advanced foldable design from Samsung we've seen so far. The company has shown off several prototypes of foldable phones with three folding s, and even a "rollable" display, but the device described in this document could unfold to form a much larger , offering more screen real estate.
While the two inner s appear to fold toward together in Fig. 5b, the next drawing (Fig. 5c) shows the outermost s fold on top of the inner ones using two hinges (535 and 515). Once the device is in this partially folded state, a can fold it once again, along the middle hinge (525).
As a result, we see a considerably thick but compact foldable phone in Fig 5d, which can be fully unfolded to form the handset seen in Fig 5a. We can also see another view of the device when it is fully folded in Fig 5e.

More drawings of the foldable seen in the patent document (tap to expand)
Photo Credit: WIPO/ Samsung
Earlier this week, another a tri-fold phone with two hinges and S Pen .
It is unclear whether Samsung plans to turn the foldable device with four s described in the patent application into a commercial device. The company typically showcases some of its latest display prototypes that aren't ready to be launched as consumer devices, and we might see a preview of the purported foldable device in the future.