MA2144 - Celtic rattleback

Celtic rattleback (also known as an *anagyre*)
When you spin a rattleback—placed with its rounded side down—on a flat surface, it behaves differently depending on the direction of rotation: in one direction (e.g., clockwise), it spins stably as expected until friction brings it to a halt; this is known as the object's preferred direction of rotation. In the opposite direction, however, the rattleback quickly slows down while beginning to wobble along its longitudinal axis. Once the spinning motion has fully transitioned into a wobbling oscillation, the rattleback begins to rotate in the direction opposite to its original spin.

left-handed rotation
Wood,
nature
approx. 115 x 39 x 18 mm