Only the axes of maximum and minimum moment of inertia are free axes of rotation around which a body can rotate stably without mechanical support. Attempts at rotation around other axes lead to wobbling, i.e. unstable rotation. A piece of styrofoam in the form of a parallelepiped (like a cigar box) is thrown into the air while giving it a spin. In order to watch the motion, opposing surfaces have been marked with different colors.