Ok I was about to do a normal comics motion background but I made it quick and all by the sudden I realyzed that I've made something different...
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Make a new document with any size (I used 500*500 px).
Now go Filter>Render>Clouds.
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Now Filter>Pixelate>Mezotint and set long stripes.
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Last step - Go to Filter>Blur>Motion Blur, set distance to 999 and any angle.
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Here is the practical use of this background:
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More Tutorials: 
