According to a report by LetsGoDigital, LG is working on a new OLED display with a side rolling screen.
The design patent was awarded to LG by The Hague International Design System.
To pull the screen out, you can do it from either side of the unit. According to the patent document when the display is fully rolled up it resembles a tall speaker, with the screen wrapped around a pair of vertical columns that extend outward from the base.
LG has been investigating rollable screen technology before, here, here and here, but those models were all rollable up and down, not side to side like this prototype.