Angle Test

I propped a hardcover notebook against a wooden pen cup to calibrate an incline. The slope looked steep enough to test rolling resistance. I placed a rounded brass paper fastener at the top ridge and let it roll. It tracked straight down the textured cover, crossed onto the desk mat, and veered left at the seam. One small ridge in the stitching altered the entire path. I adjusted the notebook by half an inch and noted the new trajectory on my pad.