I'm trying to figure out how to shade the area bound by 2 lines on a graph, and one of the axes on an x-y plot (technically, the area bound by 2 nullclines on a phase-plane plot). I've mucked about with pspicture, and made several attempts using psclip (based on a guess, and some online examples of shading between functions with >1 intersection point), but without much success. In the following (rather poor) MWE, I've left the axis ticks and labels, to help ordinate. Basiclly, I want to shade (in some color) in the upper=left area bound by the two lines. [If it matters, the two lines intersect at (1.94,2.44).]

Ultimately, I'm looking to generate something looking more or less like this:

[![enter image description here](https://i.stack.imgur.com/ZfBHG.jpg)](https://i.stack.imgur.com/ZfBHG.jpg)

Many thanks in advance to points on how to accomplish with pspicture (although I'm open to alternatives -- say, using tikz).

```
\documentclass{article}

\usepackage{pstricks-add}

\begin{document}

\begin{pspicture}(-3.5,-0.5)(4,7)
\begin{psclip}{
\pscustom[linestyle=none,algebraic,plotpoints=2000]{
\psplot[algebraic,plotpoints=20,yMaxValue=5.6%,linecolor=cyan
]{0}{2}{x*(-5.5/3.5)+5.5}%
 \psplot[algebraic,plotpoints=20,yMaxValue=5.6%,linecolor=cyan
   ]{0}{2}{x*(-4/5)+4}
   }
  }%
     \psframe*[linecolor=cyan,fillstyle=solid](2,2.2)(4,5.5)
   \end{psclip}
 \psplot[algebraic,plotpoints=20,yMaxValue=5.6%,linecolor=cyan
  ]{0}{3.5}{x*(-1.57143)+5.5}
   \psplot[algebraic,plotpoints=20,yMaxValue=5.6%,linecolor=cyan
  ]{0}{5}{x*(-4/5)+4}
  \psaxes{->}(0,0)(0,0)(6,6.5)
 \uput[-90](5.9,-.1){$H$}
 \uput[-135](-.1,6.7){$P$}
 \end{pspicture} 

  \end{document}

```