How would you do a foldable book style screen though? Even if you can make a screen that folds and bends how does the phone know how much you've tucked behind t

How would you do a foldable book style screen though? Even if you can make a screen that folds and bends how does the phone know how much you've tucked behind the phone. It's going to be awfully floppy unless you use some material that can stiffen on command. Another problem would be the thickness of the screen. If it is uniformly thick then the phone will half in thickness going from phone to tablet and if the guts of the phone are hidden underneath one half of the screen then when you lay it flat the gubbins of the phone will stop the phone/tablet from sitting flush with whatever you put it on. And the weight won't be balanced. Seems like a ton of problems just to stop one from carrying a 300gram tablet.