Happylab, the pattern is in the book Rotary Cutting Revolution: New One-step cutting by Anita Grossman Solomon.
Mine isn't entirely correct. The order of the strips is 2 light, 3 medium, 2 dark. I did mine more scrappy and used what I had. So the values I used were light-medium-dark in relation to each other, not necessarily true values. That's why there are lighter and darker areas in mine.