At work we are currently awaiting some answers to some questions, and I was explaining the delay over dinner in this manner. Suppose I wanted to talk to Great-grandmother. First I would talk to Mom, then Mom would talk to Grandmother, then Grandmother would talk to Great-Grandmother. And Great-Grandmother would reply in reverse. Or, if I wanted to talk to Grandfather, then I would talk first to Mom, and Mom would talk to Grandmother, and Grandmother would talk to Grandfather.
And the Big Sister said, If I wanted to talk to the Little Sister, I would just talk to the Little Sister.