It’s a Himitsu-bako that has 18 plates and 33 moves. I call 8 plates they are placed like the equator of the earth, “main mechanism.” They move like “4 moves Himitsu-bako” as a whole. Well, there are 10 plates placed like a cross on right and left hemispheres. I call them “substitution mechanisms.” When you slide plates, the sub mechanisms will obstruct the main mechanism with a timelag. Then, you will have a hard time to open and close. not for sale