{HEAD ~ elements} in the key and in {TAIL ~ the lock} which prevent the lock from changing from the locked condition to the unlocked condition when the key is not connected to the lock and which permit the lock to change from the locked condition to the unlocked condition when the key is connected to the lock, 
in
{ HEAD ~ elements } in the key and in { TAIL ~ the lock } which prevent the lock from changing from the locked condition to the unlocked condition when the key is not connected to the lock and which permit the lock to change from the locked condition to the unlocked condition when the key is connected to the lock ,
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH