9Chain

Ancient Chinese toys, many emperors childhood have played the original simple, complex operation, as to how to play, then what you want to test
Note: Please download 3dm stl file or files, gcode file is used to ormerod1
google translation

2014-10-17
There are many names, such as: the West is called "Chinese ring (Chinese Ring)". Italy called "Cardin ring (Cardan's Rings)". Venice called "King Solomon's seal (Sigillo Salomen).


Wiki to learn more mathematics.
http://zh.wikipedia.