He explains that brainteasers like the nine magic rings, which are based on the binary principle, were once known as "a way to keep your guests from leaving." It's a pity that today, they are likely as not to scare them away.
他說，過去像九連環這種二進位原理的巧環玩具，被稱為「留客計」，如今卻變成「逐客計」，只要一拿出來，大家避之唯恐不及，實在很可惜。