The molecule-like trios of spheres on this desk-top mobile spin and twirl gracefully as the central pendulum swings. The motion is continuous and, at first glance, impossible to fathom. The secret lies in the base; a battery-powered motor spins a powerful magnet, which in turn exerts a force on the pendulum, which in turn incorporates magnets that influence the movement of the three 'wheels'. Even when you know exactly how it works, the perpetual, rhythmic movement and gravity-defying structure still fascinate. Packed with retro geek-appeal, this is an excellent curiosity gift line for adults.