For Chinese who attach a great importance to the development of children's wisdom, jigsaw puzzle ("Qiqiaoban"）might be the most ideal choice. Composed of 7 pieces in a certain shape, this toy requires one's brain exertion to join those pieces into a given pattern without leaving any gaps. The puzzle ring is another well-known game. It is said to originate from the Warring States Period (476-221 BC). Appearing to be one of the most incomprehensible games in the human history, it even aroused the attention of Western mathematicians. To separate the nine rings which are buckled together or to join separated nine rings together is quite intricate indeed.