A scene consists of a sign and a unique ostensive context.
On the originary scene, members of the group are positioned and jointly focused around a central object of desire which is named, and thus deferred, via the originary sign. The meaning of this sign is directly tied to the specific context of its inaguration, such as the physical characteristics of the central object, the orientation of group members around the object, the time of day, etc. The word scene describes the context which every sign's meaning is bound to.
Every scene, every event, is modeled on, and an iteration of, the Originary Scene/Event. Once the Originary Scene "works" and is iterated on such that Linguistic Presence is able to extend over nonritual communication within the community, the size of the group involved in the scene can become arbitrarily large (although always remaining in a Centered Ordinality).
If we ask, how do we determine the boundaries of a scene and the end of an event, the only answer can be, upon another scene, in another event. A scene is composed, or, an existing scene is adapted, so as to concentrate focus on the center—it’s easy to think of examples, such as ritual scenes, but also theaters and lecture halls. To identify the boundaries of the scene is to construct another scene within or surrounding that scene.