title: Gnuplot color interpolation for set of linear functions
body: <p>I want to plot N different linear functions in a graph using gnuplot.
  Furthermore, I have to colors, lets say red and black.</p>
  
  <p>I want to plot all functions with different colors, so that the first function is red, the Nth is black, and the color of all functions in between is interpolated.</p>
  
  <p>How can I do this using gnuplot?</p>
  
  <p>Note: N is not fixed, so I would like gnuplot to do the interpolation.</p>
  
  <p>Something like this, which I quickly hacked together in Paint:</p>
  
  <p><img src="https://i.stack.imgur.com/kfh7A.png" alt="This picture shows what I am talking about."></p>