The idea is that a participant at a larp will encounter clues or incentives in much the same way as someone pulling random marbles out of a bag.
The metaphor of the bag of marbles is used in figuring out probability in math.
(a topic [[Erlend Eidsem Hansen]] studied during his early years in object oriented computer programming.)
This is contrary to reading a book (which is a chronological action, page after page, scene after scene, like a railroad has stations along the line). It is also contrary to playing most computer games (which usually has a branching structure in the storyline, that you get alternate ways but the interactivity is deciding alternate actions and getting alternate endings. It is not a free choice, it is a limited list of choices in one scene. The Swedish Interactingarts Collective would name this in their book "Deltagerkultur" as Interactivity, but not as Interaction).
Scene structure - the modern interpretation