This explanation isn't correct, since a running `less` would not close the pipe and is still a reader. Writes to the pipe would block until `less` fully consumed it, or until `less` was quit such as with the `q` command.

The text _is_ correct if you add a missing step to `q`uit out of the `less` program. I think this step must have been dropped along the way. Unfortunately the screen capture doesn't show this step either.