A "Reverse" Startup Oscillation? I have a very flexible plastic ruler 61cm long, 5cm wide, and .2cm thick. I hold it by one end, with the "width" vertical, and sight along the ruler "aiming" at any vertical edge (like a door jamb). When I quickly move the ruler to the left a couple of centimeters the free end first moves to the right, and Then follows to the left. It seems as if the free end of the ruler is counter-rotated about an axis as the force acts to move the first portion of the ruler. What is the explanation?