Consider the space $S$ defined by $S:=\{ (x,y) \mid 2x+y=2,~x,y \geq 0 \}$.
Find the extreme points and the extreme direction of $S$.
I found that there are two extreme points : $(1,0)$ and $(0,2)$.
But I am stuck for the extreme directions, I don't know how to see graphically the extreme directions for this space $S$.