an event type in which one participant acts upon another participant, and the second participant acts on a third participant in the same way, and so on; and the construction expressing such an event. That is, each participant in the chain is both the initiator and endpoint of transmission of force for the same type of action – except the first in the chain, who is only an initiator, and the last, who is only an endpoint. Example: in The guests followed one another into the room, each guest is a follower and a 'followee', except the first and last in the chain. It is also possible to have a closed chain, as in people following each other in a circle, in which all participants are both initiator and endpoint. (Section 7.2)