My son is 4 years old and very into trains, and we&#x27;ve lots of trips to local train switchyards together.  It&#x27;s interesting how similar it is to the Internet: packets (shipping containers) are received from input devices (ships) at ports (ports).  Routers (switchyard) send them along lines towards their destinations.  The first people to be called hackers were those in the MIT model railroad club who tinkered with the electrical stuff under the table.