title: How to overlay contour plots in Julia (using Plots with PyPlot backend)
body: <p>I'm trying to overlay two contour plots in Julia using Plots with PyPlot backend. Is it possible, and, if so, how?</p>
  
  <p>An MWE could look something like this:</p>
  
  <pre><code>using Plots
  pyplot()
  a = rand(50,50)
  b = rand(50,50)
  p1 = contour(a,seriescolor=:blues)
  p2 = contour(b,seriescolor=:reds)
  plot(p1,p2,layout=1)
  </code></pre>
  
  <p>(This code generates <code>ERROR: When doing layout, n (1) != n_override (2)</code>. I do understand the error, but I do not know how to get around it.)</p>