Back in the days when I was just a pup I was working in a department store chain that had numerous stores in Oregon and California. One evening (when the boss was away, most likely) I happened into the telephone equipment room and found a store telephone dialing guide. One section contained inter-location dialing codes! After I thought about this listing for a while I guessed I could call from one store to another, to another and to yet another. Finally I was able to make a chain of tie line calls a dozen or so stores away and then loop the chain back on itself and cause another phone in my same room ring! Knowing nothing of how telephones worked I was astounded by this feat of black magic! I also recall that one could hardly hear across this lengthly chain of tie lines -- that is, a radio playing onto the first telephone almost couldn't be heard in the final phone!
Al[TELECOM Digest Editor's Note: Some of those tie-lines were absolutely rotten, accoustic-wise. Some of them sounded like you were talking into a barrel; others would snap at you off and on. PAT]