12 to 16 is kinda stretched (I know is concept but) , yet it's still usable has applications. however I imagine more of 14 inch wide(16/9) turned into 15.6 TV proportions (5/4). Screen will stay horizontal but will gain height (almost three inches when I did comparison).
While the ThinkPad X1 already features a decent folding screen, Lenovo is willing to explore other flexible panel solutions such as the rollable display alternative that is perhaps more aesthetically pleasing, although could prove more expensive to implement at first.