I have 9 units in this year's lessons. I have about 17 lessons per unit. I have 4 periods of classes, period #1, period #2, ect. I have just created "unit #1" folder. I also created "lesson #1, lesson #2, etc" lessons. I now have empty folders labeled "period #1, period #2, etc" I would like to copy these empty folders into each lesson folder. Any way to do this efficiently?