title: How to combine matplotlib figures into multiple subplots?
body: <p>Using <code>matplotib</code> I have several <code>Figure</code> objects being returned from different plotting functions. The figures are expensive to produce with specific formatting for each one, <code>[fig1, fig2, fig3, fig4]</code>.</p>
  <p>I need to arrange these in different layouts. For examples a column containing fig1, fig3, fig4; a row containing all figures; a 2x2 grid of all figures, and so on.  I looked at <code>pyplot.subplots</code> but this returns an array of axes that cannot be set.</p>
  <p>How do I combine these separate figure objects into multiple subplots?</p>
  <p>My actual case has 20+ expensive figures that need to be arranged in several different layouts so I really cannot re-plot the figures for every layout combination.</p>