title: Imagemagick convert several commands
body: <p>after I received an answer: <a href="https://stackoverflow.com/questions/40157679/imagemagick-combine-serveral-commands">Imagemagick combine several commands</a>
   - a new question arose. I have image a, b, c, d and e
  and I want to colorize and compose them in a specific order 
  Like that: </p>
  
  <p><code>a.png b.png -composite -gravity center -channel RGB -evaluate multiply 0.9 step1.png</code> </p>
  
  <p><code>c.png d.png -composite -gravity center -channel RGB -evaluate multiply 0.9 step2.png</code> </p>
  
  <p><code>step1.png step2.png e.png -composite -gravity center result.png</code></p>
  
  <p>but in one command like that</p>
  
  <p><code>((a.png b.png -composite -gravity center -channel RGB -evaluate multiply 0.9) (c.png d.png -composite -gravity center -channel RGB -evaluate multiply 0.9) -composite -gravity center) e.png -composite -gravity center result.png</code></p>
  
  <p>but with brackets it doesn't work. Is there a way to achieve this?</p>