Description 
plot_feasible(A, b, c, lower_b, upper_b, varargin)
Plots the feasible region of the 2D linear program
maximize f = c'*x
subject to A x <= b
on the region bounded by lower_b and upper_b.
It can plot the region, bounding lines, their intersection points and vertices of the feasible region along with the maximum. Its primary use (for me) is for students learning Linear Algebra.
Its has lots of options for making the plot look pretty, or annotating vertices, etc. And you can put isoobjective function lines across the plot to help. Multiple feasible region plots are also possible, to show overlaps.
