Kongmingsuo, also known as Bagua Lock and Luban Lock, is a fixed combination of ancient civil and architectural traditions in China, and it is also an intellectual toy widely circulated in China. There are other names, such as "Don't be dull", "Liuzi Lianxiang", "Do nothing" and "Difficult Wood". The solution diagram of Kongmingsuo 12 root is as follows:

No matter which direction is facing you, press that piece of wood, as shown. When pressed, the block will slowly fall, but don't let it fall. Grab it with your fingers to the right and then push the upper bar to the left. After pushing, 12 pieces of wood dispersed in a hubbub and began to assemble. When assembling, divide the block into 1 1+ 1, and 1 is the one with the groove. According to the picture below, first build it with 4 pieces of wood.

After the erection is completed, use 2 pieces of wood and arrange them upward as shown in the figure. After placing, use 2 pieces of wood and align the gap with the 4 pieces of wood in the middle, as shown in the figure. After the first floor is put in place, repeat the previous step and put the second floor with 2 boards.

Kongmingsuo, without nails and ropes, is completely supported by the connection of its own structure, just like a piece of paper folded in half, showing a seemingly simple but extraordinary wisdom. According to legend, Kongmingsuo was invented by Lu Ban from the late Spring and Autumn Period to the early Warring States Period. In fact, this is just a legend. It originated from the tenon-mortise structure in ancient buildings in China.