Semaphore line

Imagine you're standing in a big field with your friend who's very far away. You both have flags, one red and one green, and you want to send messages to each other without shouting.

A semaphore line is like having a bunch of people in the middle who can see both of you and pass messages back and forth. Each person has two flags just like you, and they stand in a row so they can see each other.

When you want to send a message to your friend, you hold up your flags in a certain way. For example, if you hold your red flag up high and your green flag down low, it means that you want to meet your friend at the big tree. The person closest to you who can see your flags will see your message and pass it down the line by holding up their own flags the same way.

Eventually, the message reaches your friend who can read the flags from far away. They can then send a message back to you in the same way. This is called a semaphore line. It's like an invisible thread connecting you and your friend, so you can talk without shouting.