Apple has filed a patent application for a foldable device, which folds inwards much like the Samsung Galaxy Fold. In Apple's patent the device has a display layer and a protective cover layer on top that are designed to fold or bend along a specific bendable region (like the hinge on the Fold). The protective layer (which will be on top of the display layer) will reportedly be made of a ceramic material like glass, sapphire or zirconia. The figure below shows a folding device with the display on the inside, folding in on itself (figures 1A and 1B). It's unclear what we see in figure...
Source: https://www.gsmarena.com/apple_granted_patent_for_foldable_device_heres_what_it_could_look_like-news-37290.php
