@Markiyan Hirnyk 

Thank you.  That is very helpful.  

Do you know if there is a way to add dotted lines representing the non-redundant inequalities?  What I am ultimately aiming for is to produce something similar to the figure below where there are dotted lines projected onto the three planes.

@Markiyan Hirnyk 

Sorry, I wasn't very clear.  By omitting p0 I meant not having an axis for p0 on the plot and allowing p0 to take any value.  So for example the point (p1=6,p2=11,p3=0) is included in the polyhedral if there is some x such that (p0=x, p1=6,p2=11,p3=0) satifies all the inequalities.

As simple example going from 2d to 1d would be going from y > 1, 0 < x-y, x < 3 to plotting 1 < x, x < 3.