Using Taxis to explain the Sherry method: Imagine a taxi with exactly four passenger seats. In the old way of doing things, sometimes a seat has a person, and sometimes it is empty. But even when a seat is empty, the taxi still takes up the same amount of space on the road and burns the same amount of fuel. The empty seat is WASTED SPACE. The Sherry method introduces a clever new rule: Every taxi must carry exactly THREE passengers, leaving exactly one seat EMPTY. Because you know there will always be exactly one empty seat, you can use the position of that empty seat to send a secret message to the taxi driver: - If the front seat is empty, it means "We are going North." - If the back-left seat is empty, it means "We are going South." - If the back-right seat is empty, it means "We are going East." Etc. Now, the empty space isn't wasted anymore. That 0 value is doing a job. @TencentHunyuan