US Patent 7333277 Cap device for multiple image display

The cap device contains a number of prisms housed inside a closed space formed by a transparent cover, a ring, and a base. Gear teeth are provided along the inner circumference of the ring, which engage a gear member of the cap device to drive a passive gear located at an end of one of the prisms. As the other ends of the prisms are connected by a shaft of the cap device, all prisms are rotated synchronously. For every 120° spin of the prisms as the ring is turned, the faces of the prisms are aligned to face upward, and the images on the faces jointly form a complete image. As such, three complete images are revealed sequentially and continuously as the ring is turned in one direction.