title: Plot of categorical data using R
body: <p>I've a list of protein names(P1,P2,...,Pn) and they are categorized to three different expression levels High(H), medium(M) and Low(L) as measured in three experimental conditions (Exp1,Exp2, and Exp3).
  <img src="https://i.stack.imgur.com/utkQw.png" alt="enter image description here"></p>
  
  <p>I wish to make a plot as shown in the bottom part of the figure, with the name of the proteins at the left and name of experiments along the top and high, medium and low categories are indicated by Red,blue and green respectively.</p>
  
  <p>I'm new to R, I would much appreciate any help.</p>
  
  <p>Thanks in advance</p>