Old is gold indeed. Most children in the world used/use to play a threaded toy in their hands. The toy was just used for fun but it has been realized that the toy is very useful in medical diagnosis. It is also known as a button spinner, buzzer or spinning disk. It is a simplistic child's toy, with a button or disk threaded through two strings that are affixed to handles. A child begins by winding the strings and then pulling on the handles to make the threads unwind and the button spin. Pulling and relaxing the strings repeatedly makes the button spin faster.
