After introducing smartphones with curved displays, Samsung is now up for a foldable smartphone. The first time something of this sort came in the news was back in 2015 when Samsung was rumoured to have working on a foldable smartphone but it never happened to date. Later on, this year in April, a reports suggested that the foldable smartphone code-named Project Valley will now be revealed next year. Apart from rumours of the concept we never really got to see the actual design and ergonomics until today.
A patent revealing sketches of the design was spotted today. At first glance what appears to be a flip phone is actually a foldable device with a hinge just like Microsoft’s Surface Book. The hinge helps the phone be both upright just like any other smartphone but also allows it to bend when needed. However, the known issue with Microsoft’s Surface Book of dust particle getting settled on the inside of the hinge is a possibility here. Nevertheless, Such concept can be used for big sized phones which can be folded for easy portability. 
From the pictures, the front of the device features Samsung trademark home button with a capacitive back button on the right and the traditional Menu button the left indicating that Samsung might be working on this phone from the time when company’s smartphones used to come with that ‘Menu’ button.
Samsung already introduced curved display with Note EDGE line up back in 2014 after which the curved concept was carried forward to both S series and Note series.
Talking about the S series, famous Tipster Evan Blass (@eveleaks) today revealed model numbers of the Galaxy S8. Samsung Galaxy S8 will reportedly come in two variants with model numbers SM-G950 and SM-G955. Not only this, Evan also stated that a smartphone with model number SM-N950 is also in works which might be the next Galaxy Note.