At Fading Motion, a swinging pendulum pours sand from its “bob” onto a variable-speed conveyer belt that moves in a direction perpendicular to the swing of the pendulum. The sand forms a wavy pattern on the belt that exponentially diminishes in amplitude due to a damping mechanism on the pendulum consisting of a paddle moving through thick oil. The oil reservoir may be raised or lowered to vary the amount of damping. If no damping is employed, a fairly regular sine wave is produced; the frequency of the wave depends on the speed of the belt. Children love to draw with the sand pendulum by simply moving the pendulum with their hands.