Protesters formed 'a human chain' [=they stood next to each other with their arms linked] around the ancient tree to prevent it from being cut down.
In the United States, the President as the commander in chief is at the head of the military 'chain of command'.
I thought he really won the lottery but he was only 'pulling my chain'. [=he was only playing a joke on me]
(..) inside the swarm it might *something* effect capacity the way it coordinates. It will have to be the frequency they will not anticipate. It will cause a chain reaction that will wipe out the whole swarm. Sir, a closed network like that might be sensitible to very high frequency. VHF. Radio. (..)2016 Star Trek Beyond